Merge pull request #280 from sergeyklay/master

Minor fixes & additions in Permission
Update feature: Working user level permissions; needs testing
Fixed issue: fix the admin/permission/user exception errors
Fixed issue: remove accidental comment in previous commit in ACL::check()
Update Feature: Cleanup role cache when role updated or deleted
Update Feature: Remove submission support in admin/permission/list
Update Feature: Cleanup admin/permission/list
Updated feature: Update userguide credits
Fixed issue: Including redactor.css file only where it's needed