Only use image loader on images in main_content.
Refactors archive image zoom.
Adds image spinner to archive overlay ajax calls.
Image loader spinner for cropper overlay.
Uses dialogclose event for destroying image cropper in overlay.
Display thumbnail spinner after leaving the image cropper.
Uses 'c' parameter to crop image from the center of the image.

gravity: '#' did not what we expect, but gravity: 'c' does.
Use Attachment.file_name instead of filename in the file assign view

Use Attachment.file_name in _essence_file_view.html.erb for the frontend.
This prevents an exception because filename is not implemented.
Merge pull request #367 from pascalj/master

Use Attachment.file_name in _file_to_assign.html.erb
Respect upsample param in all picture processing methods.
Upgrades to capybara 2.0 and poltergeist 1.10.

Moves integration tests into feature folder
Implements multiple roles per user feature.
Adds a screenshot note for periodically failing test on travis.
Updates travis settings to support phantomjs 1.8 and ruby 2.0
verbose output for phantomjs install script on travis ci
[CI] Adding debug infos for phantomjs install
[CI] Do not install phantomjs 1.8.1, on Travis. Its already installed.
Removes default role from users table.
Adds new codeclimate and gemnasium status badges to readme. [ci skip]
Changes users roles column type back to string.