Rewrote merge_requests.js as coffeescript and updated code
Created by: koenpunt
Rewrote merge_request.js as coffeescript.
Updated the naming of classes to be less specific and more hierarchical e.g.:
.mr_nav_tabs becomes .merge-request .nav-tabs where .nav-tabs is already a global element for navigation tabs.
Same for .merge-request-diffs => .merge-request .diffs, .merge-request-notes => .merge-request .notes etcetera.
And this way actually all elements of the merge request page are wrapped inside a div with class .merge-request
