Rewrite of F3 - Automatic Body Removal

See https://github.com/ferstaberinde/F3/issues/81

Removed remnants of FIFO method.
Now takes distance to player unit into account (controlled by variable set in init.sqf)
Removes dead unit's group if they are empty.
Script triggered by eventhandler is run server-side (as effects are global).


Note:
As the effects of deleting a body/group are global there's no need to have the script fired by the killed eventhandler run anywhere else but serverside (the old method ran it on every client). f/common/f_addRemoveBodyEH could thus be run server-side as well, as long as I'm missing something.