Using action key with hammer will destroy stuff. Need to improve functionality.

Using action key with hammer will destroy the closest building/object.  This is good except there should be an option added.  If enabled, it will work like currently.  IF disabled, hammer will only hammer non-player placed objects.  So if the object is built by a player, the hammer will not target/destroy it using the action key (you can still hammer it manually with clicking).  Therefore with this optino disabled, only non-player placed/built objects will be targeted by the action key while holding a hammer.