[NEW] Add new Documents\Interfaces\Activable interface

Apply interface to Catalog_Condition, Catalog_Price, Media_Image, Theme_PageTemplate, Theme_Theme, User_User,
Website_Menu, Website_Text and Workflow_Workflow documents

Remove Publishable interface on Catalog_Shop document.
Remove publishable attribute
Fix OAuth tests
Merge pull request #252 from inthause/documents

Add new Documents\Interfaces\Activable Interface.