Add checksum support to Casks.

`md5`, `sha1`, `sha256` all take a hexdigest string, e.g:
sha1 'f645e9da45a621415a07a7492c45923b1a1fd4d4'

`no_checksum` takes no argument, and indicates there is no checksum
for this cask. This is *not recommended*, and should only be used for
casks that have no versioned downloads.

`brew cask install` will complain if there is no sum provided (unless
`no_checksum` has been invoked), or if the sums do not match. It will
provide the computed checksum so the cask can be easily amended.

Adapted from @passcod's work in 82cc199

Casks/adium.rb

@@ -3,4 +3,5 @@ class Adium < Cask
   homepage 'http://www.adium.im/'
   version '1.5.3'
   content_length '23726161'
+  sha1 'ea16f7b65b8b37caa9025f4d68c0dd71845a4027'
 end

Casks/alfred.rb

@@ -3,4 +3,5 @@ class Alfred < Cask
   homepage 'http://www.alfredapp.com/'
   version '1.3.1_261'
   content_length '2706582'
+  sha1 '92bc216c0b0e1e49d4b98c33971274848ccbb4e1'
 end

Casks/anvil.rb

@@ -3,4 +3,5 @@ class Anvil < Cask
   homepage 'http://anvilformac.com/'
   version 'latest'
   content_length '2322000'
+  no_checksum
 end

Casks/aquamacs.rb

@@ -3,4 +3,5 @@ class Aquamacs < Cask
   homepage 'http://aquamacs.org/'
   version '3.x Nightly'
   content_length '50220871'
+  no_checksum
 end

Casks/arq.rb

@@ -3,4 +3,5 @@ class Arq < Cask
   homepage 'http://www.haystacksoftware.com/arq/'
   version 'latest'
   content_length '9118163'
+  no_checksum
 end

Casks/at-monitor.rb

@@ -3,4 +3,5 @@ class AtMonitor < Cask
   homepage 'http://www.atpurpose.com/atMonitor/'
   version 'latest'
   content_length '1380053'
+  no_checksum
 end

Casks/back-in-time.rb

@@ -3,4 +3,5 @@ class BackInTime < Cask
   homepage 'http://www.tri-edre.fr/english/backintime.html'
   version '2.0.3'
   content_length '7532553'
+  sha1 '3c30818d789f5b7da9645f7dd2784b7183f1caf1'
 end

Casks/bartender.rb

@@ -3,4 +3,5 @@ class Bartender < Cask
   homepage 'http://www.macbartender.com/'
   version 'latest'
   content_length '4380381'
+  no_checksum
 end

Casks/bettertouchtool.rb

@@ -3,4 +3,5 @@ class Bettertouchtool < Cask
   homepage 'http://blog.boastr.net/'
   version 'latest'
   content_length '3527830'
+  no_checksum
 end

Casks/boot-x-changer.rb

@@ -3,4 +3,5 @@ class BootXChanger < Cask
   homepage 'http://namedfork.net/bootxchanger'
   version '2.0'
   content_length '694615'
+  sha1 'bc8c80913ba09c1fc2f354b954b321f261bb2e36'
 end

Casks/brackets.rb

@@ -3,4 +3,5 @@ class Brackets < Cask
   homepage 'http://brackets.io'
   version 'sprint-16'
   content_length '25020067'
+  sha1 '94322762ecb00baab857e324a98e543d548bf961'
 end

Casks/caffeine.rb

@@ -3,4 +3,5 @@ class Caffeine < Cask
   homepage 'http://lightheadsw.com/caffeine/'
   version '1.1.1'
   content_length '260503'
+  sha1 'd2fbdad1619934313026fc831e6c6e3dd97ac030'
 end

Casks/candybar.rb

@@ -3,5 +3,6 @@ class Candybar < Cask
   homepage 'http://panic.com/museum/candybar/'
   version '3.3.4'
   content_length '133007800'
+  sha1 'f645e9da45a621415a07a7492c45923b1a1fd4d4'
 end
 

Casks/changes.rb

@@ -3,5 +3,6 @@ class Changes < Cask
   homepage 'http://bitbq.com/changes/'
   version 'latest'
   content_length '1990799'
+  no_checksum
 end
 

Casks/chocolat.rb

@@ -3,5 +3,6 @@ class Chocolat < Cask
   homepage 'http://chocolatapp.com/'
   version 'latest'
   content_length '14545811'
+  no_checksum
 end
 

Casks/chromium.rb

@@ -3,4 +3,5 @@ class Chromium < Cask
   url 'http://sourceforge.net/projects/osxportableapps/files/Chromium/ChromiumOSX_22.0.1229.92.dmg/download'
   version '22.0.1229.92'
   content_length '43991068'
+  sha1 'afb9ae77e4aa2a6e3321ffa314869698105bb22f'
 end

Casks/clip-menu.rb

@@ -3,4 +3,5 @@ class ClipMenu < Cask
   homepage 'http://www.clipmenu.com/'
   version '0.4.3'
   content_length '1131824'
+  sha1 '9237d3f1e237f25fdd752e05d383d4b2a4274e3e'
 end

Casks/colloquy.rb

@@ -3,5 +3,6 @@ class Colloquy < Cask
   homepage 'http://colloquy.info/'
   version '2.4'
   content_length '7442191'
+  sha1 'e0f6d4df8a09c5b48e0d972dc732cc1203b2384c'
 end
 

Casks/cura.rb

@@ -3,4 +3,5 @@ class Cura < Cask
   url 'http://software.ultimaker.com/current/Cura-12.11-osx64.dmg'
   version '12.11'
   content_length '92558002'
+  sha1 '8fa56ce33d6a8d7604858e20273635ce3d926b7d'
 end

Casks/cyberduck.rb

@@ -3,4 +3,5 @@ class Cyberduck < Cask
   homepage 'http://cyberduck.ch'
   version '4.2.1'
   content_length '24746156'
+  sha1 '6f1e220830f324ba136b4301b12711f6037176c7'
 end

Casks/dia.rb

@@ -3,4 +3,5 @@ class Dia < Cask
   url 'http://downloads.sourceforge.net/dia-installer/dia/0.97.2/Dia-0.97.2-5.dmg'
   version '0.97.2-5'
   content_length '33631850'
+  sha1 '20bcc65b63f44aaa2788a7183c4a254f6a57d57d'
 end

Casks/disk-inventory-x.rb

@@ -3,4 +3,5 @@ class DiskInventoryX < Cask
   homepage 'http://www.derlien.com/'
   version 'latest'
   content_length '2969560'
+  no_checksum
 end

Casks/divvy.rb

@@ -3,4 +3,5 @@ class Divvy < Cask
   homepage 'http://mizage.com/divvy/'
   version 'latest'
   content_length '2377821'
+  no_checksum
 end

Casks/dropbox.rb

@@ -3,4 +3,5 @@ class Dropbox < Cask
   homepage 'http://www.dropbox.com/'
   version '1.4.20'
   content_length '22599357'
+  sha1 'cd750534342da71e0eba45f2c9b184242abeadbd'
 end

Casks/emacs.rb

@@ -3,4 +3,5 @@ class Emacs < Cask
   homepage 'http://emacsformacosx.com/'
   version '24.2'
   content_length '55354843'
+  sha1 '0f5d368420d410ab395d7aedcf63f5cc6e6aaf85'
 end

Casks/firefox-aurora.rb

@@ -3,4 +3,5 @@ class FirefoxAurora < Cask
   homepage 'http://www.mozilla.org/en-US/firefox/aurora/'
   content_length '49254741'
   version '19.0a2'
+  no_checksum # This is a nightly
 end

Casks/firefox.rb

@@ -3,4 +3,5 @@ class Firefox < Cask
   homepage 'http://www.mozilla.org/en-US/firefox/'
   content_length '34958026'
   version '17.0.1'
+  sha1 'a9888ce69440574fabff712549c8ff503fd1acb7'
 end

Casks/fluid.rb

@@ -3,4 +3,5 @@ class Fluid < Cask
   homepage 'http://fluidapp.com/'
   version '1.6.1'
   content_length '2499923'
+  sha1 '7de2fe4372e9d055bd2bb6f5afcefa549740a7ce'
 end

Casks/flux.rb

@@ -3,4 +3,5 @@ class Flux < Cask
   homepage 'http://stereopsis.com/flux/'
   version 'latest'
   content_length '1314863'
+  no_checksum
 end

Casks/gephi.rb

@@ -1,6 +1,7 @@
 class Gephi < Cask
+  url 'https://launchpad.net/gephi/0.8/0.8.1beta/+download/gephi-0.8.1-beta.dmg'
   homepage 'http://gephi.org/'
   version '0.8.1'
-  url 'https://launchpad.net/gephi/0.8/0.8.1beta/+download/gephi-0.8.1-beta.dmg'
   content_length '39116463'
+  sha1 '0bd1d9d5b1da69b77217949b788597a952cbd846'
 end

Casks/gfxcardstatus.rb

@@ -3,4 +3,5 @@ class Gfxcardstatus < Cask
   url 'http://codykrieger.com/downloads/gfxCardStatus-2.3.zip'
   version '2.3'
   content_length '979240'
+  sha1 '0bd1d9d5b1da69b77217949b788597a952cbd846'
 end

Casks/gimp.rb

@@ -3,4 +3,5 @@ class Gimp < Cask
   homepage 'http://www.gimp.org'
   version '2.8.2'
   content_length '63881252'
+  sha1 '0bd1d9d5b1da69b77217949b788597a952cbd846'
 end

Casks/github.rb

@@ -3,4 +3,5 @@ class Github < Cask
   homepage 'http://mac.github.com'
   version 'latest'
   content_length '10061271'
+  no_checksum
 end

Casks/gitx-l.rb

@@ -3,5 +3,6 @@ class GitxL < Cask
   homepage 'http://gitx.laullon.com/'
   version '0.8.4'
   content_length '1383025'
+  sha1 '86517311dcdc7348e308b542e3d5aad1a304f94f'
 end
 

Casks/gitx.rb

@@ -3,4 +3,5 @@ class Gitx < Cask
   homepage 'http://gitx.frim.nl/'
   version 'latest'
   content_length '1665028'
+  no_checksum
 end

Casks/gmail-notifr.rb

@@ -3,4 +3,5 @@ class GmailNotifr < Cask
   homepage 'http://ashchan.com/projects/gmail-notifr'
   version '0.6.4'
   content_length '11837209'
+  sha1 '330a87bb9e0ed6209e6ad3f1d09e79b4c92674ef'
 end

Casks/google-chrome-canary.rb

@@ -1,6 +1,7 @@
 class GoogleChromeCanary < Cask
-  url 'https://storage.googleapis.com/chrome-canary/GoogleChromeCanary.dmg'  
+  url 'https://storage.googleapis.com/chrome-canary/GoogleChromeCanary.dmg'
   homepage 'https://tools.google.com/dlpage/chromesxs'
   version 'latest'
   content_length '58637811'
+  no_checksum
 end

Casks/google-chrome.rb

@@ -1,6 +1,7 @@
 class GoogleChrome < Cask
-  url 'https://dl.google.com/chrome/mac/stable/GGRO/googlechrome.dmg'  
+  url 'https://dl.google.com/chrome/mac/stable/GGRO/googlechrome.dmg'
   homepage 'https://www.google.com/chrome/'
   version 'stable-channel'
   content_length '56466358'
+  no_checksum
 end

Casks/google-notifier.rb

@@ -3,4 +3,5 @@ class GoogleNotifier < Cask
   homepage 'http://toolbar.google.com/gmail-helper/notifier_mac.html'
   version '1.10.7'
   content_length '1142033'
+  sha1 '9ea16ae966033a1c6a5b9d50bb9e8d5080906059'
 end

Casks/handbrake.rb

@@ -3,4 +3,5 @@ class Handbrake < Cask
   homepage 'http://handbrake.fr/'
   version '0.9.8'
   content_length '7485495'
+  sha1 'd255b4daa64cc359209e306ff9ef8a24a66e20aa'
 end

Casks/handbrakebatch.rb

@@ -3,4 +3,5 @@ class Handbrakebatch < Cask
   homepage 'http://www.osomac.com/apps/osx/handbrake-batch/'
   version 'latest'
   content_length '14008464'
+  no_checksum
 end

Casks/hands-off.rb

@@ -3,4 +3,5 @@ class HandsOff < Cask
   homepage 'http://www.metakine.com/products/handsoff/'
   version '1.5.1'
   content_length '6204375'
+  sha1 '6738476c53f73a4924fa38444c5802250b180d4f'
 end

Casks/inkscape.rb

@@ -1,6 +1,7 @@
 class Inkscape < Cask
   homepage 'http://inkscape.org'
   url 'http://downloads.sourceforge.net/inkscape/Inkscape-0.48.2-1-SNOWLEOPARD.dmg'
-  version '0.48.2-1'  
   content_length '87079397'
+  version '0.48.2-1'
+  sha1 '20073844e26dc787da04d951e3a24338758e5e8d'
 end

Casks/intellij-community.rb

@@ -3,4 +3,5 @@ class IntellijCommunity < Cask
   homepage 'https://www.jetbrains.com/idea/index.html'
   version '11.1.4'
   content_length '113789795'
+  sha1 '20073844e26dc787da04d951e3a24338758e5e8d'
 end

Casks/intellij-ultimate.rb

@@ -3,4 +3,5 @@ class IntellijUltimate < Cask
   homepage 'https://www.jetbrains.com/idea/index.html'
   version '11.1.4'
   content_length '198099319'
+  sha1 '9f2d70d934ac41fe522df99f1fea9ac3b44f31a7'
 end

Casks/irip.rb

@@ -3,4 +3,5 @@ class Irip < Cask
   version 'latest'
   homepage 'http://thelittleappfactory.com/irip/'
   content_length '2085303'
+  no_checksum
 end

Casks/istat-menus.rb

@@ -3,4 +3,5 @@ class IstatMenus < Cask
   homepage 'http://bjango.com/mac/istatmenus/'
   version '3.21'
   content_length '8353594'
+  sha1 '07b6a0d1f3d6c0ce30fd0e7b62ee9275405bead9'
 end

Casks/iterm2.rb

@@ -1,5 +1,6 @@
 class Iterm2 < Cask
   url 'http://iterm2.googlecode.com/files/iTerm2-1_0_0_20120203.zip'
-  version '1.0.0.20120203'
   homepage 'http://www.iterm2.com/'
+  version '1.0.0.20120203'
+  sha1 '554d2f9b9fbd7d4930f3a9b6962264bc026237c9'
 end

Casks/jumpcut.rb

@@ -3,5 +3,6 @@ class Jumpcut < Cask
   homepage 'http://jumpcut.sourceforge.net/'
   version '0.63'
   content_length '530939'
+  sha1 '6ac88694f84b549f87c7c20bbf028f1d174d9e40'
 end
 

Casks/justlooking.rb

@@ -3,4 +3,5 @@ class Justlooking < Cask
   homepage 'http://chipmunkninja.com/JustLooking'
   version '3.3.3'
   content_length '4849204'
+  sha1 'ac082882d21e77c5c77e99f8fa7bae9f72bac75c'
 end

Casks/keepass-x.rb

@@ -1,6 +1,7 @@
 class KeepassX < Cask
-  url 'http://downloads.sourceforge.net/keepassx/KeePassX-0.4.3.dmg'  
+  url 'http://downloads.sourceforge.net/keepassx/KeePassX-0.4.3.dmg'
   homepage 'http://www.keepassx.org'
   version '0.4.3'
   content_length '13423385'
+  sha1 '40f61b33f559f1de61e698b9f46b65c985a98955'
 end

Casks/keyboard-maestro.rb

@@ -3,4 +3,5 @@ class KeyboardMaestro < Cask
   homepage 'http://www.keyboardmaestro.com/'
   version 'latest'
   content_length '19842748'
+  no_checksum
 end

Casks/libre-office.rb

@@ -3,4 +3,5 @@ class LibreOffice < Cask
   homepage 'http://www.libreoffice.org/'
   version '3.5.7'
   content_length '178067623'
+  sha1 'a9c32610d9f9b50be5058c115f62d3660ae74b17'
 end

Casks/little-snitch.rb

@@ -3,4 +3,5 @@ class LittleSnitch < Cask
   homepage 'http://www.obdev.at/products/littlesnitch/index.html'
   version '2.5.4'
   content_length '3133956'
+  sha1 '217a83098c1eb3df69560e539d86ef4bc6b3b756'
 end

Casks/livestation.rb

@@ -3,4 +3,5 @@ class Livestation < Cask
   homepage 'http://www.livestation.com'
   version '3.2.0'
   content_length '34333657'
+  sha1 '7c3334e2c710d8c89bfc91591ffed56c1b74643c'
 end

Casks/macvim.rb

@@ -3,4 +3,5 @@ class Macvim < Cask
   homepage 'http://code.google.com/p/macvim/'
   version '7.3-65'
   content_length '7215380'
+  sha1 '30f58b03127a7b5f9e2c23fd31d3749e8f3e2197'
 end

Casks/menu-bar-filter.rb

@@ -3,4 +3,5 @@ class MenuBarFilter < Cask
   homepage 'http://wez.github.com/MenuBarFilter/'
   version '1.2.2'
   content_length '501304'
+  sha1 'aecadf43bdba901e254012cc21e746f39f244bd8'
 end

Casks/moom.rb

@@ -3,4 +3,5 @@ class Moom < Cask
   homepage 'http://manytricks.com/moom/'
   version 'latest'
   content_length '6121023'
+  no_checksum
 end

Casks/namemangler.rb

@@ -3,4 +3,5 @@ class Namemangler < Cask
   version 'latest'
   homepage 'http://manytricks.com/namemangler/'
   content_length '1614684'
+  no_checksum
 end

Casks/notational-velocity.rb

@@ -3,4 +3,5 @@ class NotationalVelocity < Cask
   homepage 'http://notational.net'
   version 'latest'
   content_length '2550864'
+  no_checksum
 end

Casks/nv-alt.rb

@@ -1,6 +1,7 @@
 class NvAlt < Cask
-  url 'http://brettterpstra.com/downloads/nvalt2.1.zip?9d7bd4'  
+  url 'http://brettterpstra.com/downloads/nvalt2.1.zip?9d7bd4'
   homepage 'http://brettterpstra.com/project/nvalt/'
   version '2.1'
   content_length '3587960'
+  sha1 '686183dd51701ef6f304dec07d8c9049d553185a'
 end

Casks/one-password.rb

@@ -3,4 +3,5 @@ class OnePassword < Cask
   homepage 'https://agilebits.com/onepassword'
   version '3.8.20'
   content_length '19241282'
+  sha1 'b8aaa60f32c0431a95347b8fb4e814472e89bb2b'
 end