js: Update jQuery to 2.2.4 and add jQuery Migrate plugin

Versions 1.x and 2.x no longer receive any patches, and there are likely
some uses of deprecated 1.x features in the dlang.org site.  Bump it to
the most up-to-date version that the migration plugin will allow us to
in order to flag problems. Afterwards, it should be possible to jump to
the latest 3.x version.

Author: ibuclaw

book/dlang.org.ddoc

@@ -30,8 +30,9 @@ COMMON_HEADERS_DLANG=
 <link rel="stylesheet" href="$(STATIC css/codemirror.css)">
 _=
 COMMON_SCRIPTS =
-    $(SCRIPTLOAD https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js)
-    $(SCRIPT window.jQuery || document.write('\x3Cscript src="$(STATIC js/jquery-1.7.2.min.js)">\x3C/script>');$(EXTRA_JS))
+    $(SCRIPTLOAD https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js)
+    $(SCRIPT window.jQuery || document.write('\x3Cscript src="$(STATIC js/jquery-2.2.4.min.js)">\x3C/script>');$(EXTRA_JS))
+    $(SCRIPTLOAD $(STATIC js/jquery-migrate-1.4.1.js))
     $(SCRIPTLOAD $(STATIC js/dlang.js))
     $(COMMON_SCRIPTS_DLANG)
 _=

dlang.org.ddoc

@@ -31,8 +31,9 @@ COMMON_HEADERS_DLANG=
 <link rel="stylesheet" href="$(STATIC css/codemirror.css)">
 _=
 COMMON_SCRIPTS =
-    $(SCRIPTLOAD https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js)
-    $(SCRIPT window.jQuery || document.write('\x3Cscript src="$(STATIC js/jquery-1.7.2.min.js)">\x3C/script>');$(EXTRA_JS))
+    $(SCRIPTLOAD https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js)
+    $(SCRIPT window.jQuery || document.write('\x3Cscript src="$(STATIC js/jquery-2.2.4.min.js)">\x3C/script>');$(EXTRA_JS))
+    $(SCRIPTLOAD $(STATIC js/jquery-migrate-1.4.1.js))
     $(SCRIPTLOAD $(STATIC js/dlang.js))
     $(COMMON_SCRIPTS_DLANG)
 _=

dpl-docs/views/layout.dt

@@ -30,7 +30,8 @@ html(lang='en-US')
     link(rel='stylesheet', href='#{root_dir}css/ddox.css')
     link(rel='stylesheet', href='https://maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css')
     link(rel='shortcut icon', href='#{root_dir}favicon.ico')
-    script(src='https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js', type='text/javascript')
+    script(src='https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js', type='text/javascript')
+    script(type='text/javascript', src='#{root_dir}js/jquery-migrate-1.4.1.js')
     meta(name='viewport', content='width=device-width, initial-scale=1.0, minimum-scale=0.1, maximum-scale=10.0')
 
   body.std(id='#{info.node.moduleName}')
@@ -228,10 +229,12 @@ html(lang='en-US')
         #copyright.smallprint
           | Copyright &copy; 1999-#{year} by the <a href="#{root_dir}foundation_overview.html">D Language Foundation</a> | Page generated by <a href="https://github.com/rejectedsoftware/ddox">ddox</a>.
 
-    script(type='text/javascript', src='https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js')
+    script(type='text/javascript', src='https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js')
     |     
     script(type='text/javascript').
-      window.jQuery || document.write('\x3Cscript src="#{root_dir}js/jquery-1.7.2.min.js">\x3C/script>')
+      window.jQuery || document.write('\x3Cscript src="#{root_dir}js/jquery-2.2.4.min.js">\x3C/script>')
+    |
+    script(type='text/javascript', src='#{root_dir}js/jquery-migrate-1.4.1.js')
     |     
     script(type='text/javascript', src='#{root_dir}js/codemirror-compressed.js')
     |