Add hero-unit to /help

app/views/help/index.html.haml

-%h2.page-title
+.hero-unit
+  %h2
     GitLab
-  .pull-right
     %span= Gitlab::VERSION
     %small= Gitlab::REVISION
-%p.slead
-  Self Hosted Git Management
+  %p.slead
+    GitLab is open source software to collaborate on code.
     %br
-  Fast, secure and stable solution based on Ruby on Rails.
+    Create projects and repositories, manage access and do code reviews.
+    %br
+    Read more about GitLab at #{link_to "gitlab.org", "http://gitlab.org/", target: "_blank"}.
 
 .row
   .span4