Cannot remove user that owns a project.

Update doc/development.md

add order for projects admin page

Optimized commit diff views, now showing file size and file mode changes

Fix hooks for merge requests which were accepted by web-interface

Update Gems

Replaced commit status images (diff_file_*.png) with fontawesome icons

Fix editor

Cannot remove user that owns a project.

Make lines shorter, set alert, use path instead of url.

Add file line links

Use poltergeist instaead of capybara-webkit

Fixed a typo.

Also fixes #1983