Add access control options to topic properties to secure visibility, initial data entry and edit.  

Use cases:

1. May want user to enter specific information when creating topic, but may wish to restrict visibility of entered values.
2. May want to have a property that only admin/mod can define.  The topic author wouldn't have access to field at all other than view.  For example, in our feature requests forum we would want to be able to change the status of the request (Needs for interest, Pending Review, Under Development, Implemented).
3. May want to have a property that only admin/mod can define or view.  You may want to "flag" topics by a unique property that only certain users can see and/or modify.  This will be useful with the ability to filter topics by property.