Switchable the main branch on network graph

Fixed a grammar mistake in alert-message.block-message

Fix #2790

remove incorrect information about the api version

The API version is currently not equal to the gitlab major version number. Gitlab 4.1 
still uses API version 3. Point to the lib/api.rb file instead which contains the
autoritative information.

Added swipe view for image diff

Prepared diff view for multiple view modes

Converted commits.js to coffeescript
image info in separate coffeescript file

Added swipe view mode

Added onion skin viewMode

Updates web hooks to process via queue

Feature: Projects page