Merge pull request #271 from sergeyklay/master

Edit/Add roles
Merge pull request #272 from sergeyklay/master

Permission fixes
Update feature: updated Cerber theme
Fixed issue: Tabs in user class
New Feature: Allow admins to preview theme without enabling.

This feature allows admins to preview themes by passing a get parameter
with theme name without enabling the given theme.
Still its work in progress not finished.
Fixed issue: Fixed comment htaccess error
Fixed issue: Removed not needed file