Game : began work on Drop_Trace() which will detect places where we can
drop an item (based on where the mouse pointer is pointing).
Game : more work on Drop_Trace() function...
Game : create a 'drop_indicator' entity for each client, for showing
where the player may drop an dragged object.
Data : created a very basic place-holder "drop_spot" OBJ model.
Bit of improvement to "drop spot" handling...