Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Didn't bother with files in db/, config/, or features/

Changed "authored or assigned to you" to read "authored by or assigned to you" which reads better.

* .page_title  class added. Used for better page headers
* improved help page
* added back links for help pages
* show app version & revision on help page

Backend changes:
* Gitab::Version && Gitlab::Revision constants