Don't initialize the application during asset precompilation.

Required by Heroku.
Fix CSS includes in application.css.scss
Add controller specific assets to precompilation list
Setup mailer configuration for production environment
Include controller specific assets only if they exist
Setup the default hostname for mailers in production
Disable bot-away temporarily

until proper exceptions are added
Add a domain_name config variable
Change the default hostname to use the domain name provided through the env.
Merge branch 'master' into change_twitter_action_and_facebook_comments_URLs
Fix root_url for Twitter Action Sharing
Fix root_url for Facebook Comments