PickActor forceTID parameter

This changes the default behavior of PickActor to only set the TID if the picked actor has a TID of 0. In the case that the actor has no TID, you didn't force the TID to be changed, and you used 0 for the 5th argument, the function will return false. The 8th parameter (bool forceTID) will revert to the original behavior, potentially breaking scripts that rely on the TID.