Maya: AssetManager: 1. Added duplicate and error checking to MVC item delegates. If a value is duplicate in a column or if a field value has an error (an empty string for example), it will be formatted differently (drawn in red for now). 2. Used this opportunity to refactor the asset manager item_delegate modules and added a new module called asset_manager_item_delegate_functionality. It is composed into the delegates and encapsulates common functionality.