Per-Player Construction Heap

[darklich14]

If "last player" is tracked when entity and tile ghosts are created, then the build queue could be managed in a way similar to a preemptive OS process/task scheduler does it whereby tasks which have not gotten attention recently can be elevated. In this way, a player whose tasks have been starved by a large global queue could be serviced by adding weight for them to be serviced until they get a turn. This way no one player could squash the global queue and cause every other player to be starved out. Thank you in advance for your consideration!