RSF Bugfix

Created by: Sircrab

While using the RSF, when trying to create stuff on a table, the RSF would end up in the table because of the attackby method from the table. By overriding the method so that it first checks if the object itself is an RSF and if not passing the call to the original method, the RSF now behaves correctly and stays on the user's hand. As a consequence RSF cannot be put on tables by clicking now (Much like how wrenches cannot be put either if you click with one in your hand).