UI changes:

* .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

app/views/keys/index.html.haml

@@ -1,8 +1,11 @@
-%h3
+%h3.page_title
   SSH Keys
   = link_to "Add new", new_key_path, :class => "btn small right"
 
-%br
+%hr
+%p.slead 
+  SSH key allows you to establish a secure connection between your computer and Gitlab
+
 
 %table#keys-table.admin-table
   %thead

app/views/keys/show.html.haml

@@ -1,4 +1,4 @@
-%h3
+%h3.page_title
   Public key:
   = @key.title
   %small