Fix issue_closing_regex in gitlab.yml.example

It turns out that regex escapes and YAML quoted-scalar escapes don't play
nicely together.

Update unicorn.rb.example

[WIP]Drop support of root namespace in routing

Add "public-project?" checkbox to new-project view 

Minor UI fix in views/public/project/index.html.haml

Fix typo in installation.md

Re-enable notifying commit authors of new commit notes

* Show new merge request button from compare page
* Show message if user selected same branches
* Show message if compared branches are the same
* Prepend inputs with from/to labels

SSH is pronounced as /es es aged/, so we need "an" instead of "a".

Trigger notification service when new user-group relation was created