Install phantomjs via phantomjs-prebuilt instead of phantomjs gem

phantomjs-prebuilt has all sort of alternative CDN URLs to
ensure that phantom downloads more successfully

.travis.yml

@@ -3,11 +3,13 @@ rvm:
   - 2.3.0
 bundler_args: "--without development --without production --deployment"
 cache: bundler
+env:
+  - "PATH=$PWD/node_modules/.bin:$PATH"
 before_install:
+  - 'npm install'
   - 'echo ''gem: --no-ri --no-rdoc'' > ~/.gemrc'
   - "rvm @global do gem uninstall bundler -x && gem install bundler"
 before_script:
-  - 'npm install -g bower'
   - 'bundle exec rake bower:install:development'
   - "./config/before-travis.sh"
 script:

package.json

@@ -1,8 +1,9 @@
 {
-  "//": "This package.json currently only exists so Bower will be installed on Heroku",
+  "//": "This package.json is mostly for Heroku and TravisCI, use bin/setup for local development.",
   "name": "bridge_troll",
   "version": "0.0.0",
   "dependencies": {
-    "bower": "^1.7.2"
+    "bower": "^1.7.2",
+    "phantomjs-prebuilt": "2.1.7"
   }
 }