API: system hooks API functions and documentation updated

* updated system hooks documentation and code comments
* fixed access to system hooks if no user given resulting in a `500 Server Error`
* added tests
Merge branch 'master' into api/system_hooks_adjustments
add coveralls.io to travis builds
fixed travis env, added coverage badge
Merge pull request #3170 from Asquera/api/system_hooks_adjustments

API: system hook request functions and documentation updated
Rename to coffee.
Reduce amount of user info provided with internal api
Covert to coffee.
fix api internal test
Merge pull request #3192 from hiroponz/convert-to-coffee

Convert branch-graph.js to branch-graph.js.coffee
Search projects on dashboard was not worked. Fixed
Search fields were have same id's. Fixed
Tests improved
Tests for dashboard projects fixed
remove unused file
Merge branch 'feature/broken-projects-search-23049' of github.com:Undev/gitlabhq into new_staging

* 'feature/broken-projects-search-23049' of github.com:Undev/gitlabhq:
  Tests for dashboard projects fixed
  Tests improved
  Search fields were have same id's. Fixed
  Search projects on dashboard was not worked. Fixed
  fix api internal test
  Covert to coffee.
  Reduce amount of user info provided with internal api
  Rename to coffee.
  fixed travis env, added coverage badge
  add coveralls.io to travis builds
  API: system hooks API functions and documentation updated

Conflicts:
	Gemfile.lock