Initial wave of stress testing and a new timer, used purely for sorting
out colliding entities. When colliding entities happen, they now stack
solver timers on each other to try to sort it out. It'll work- but it
starts to crunch if more than about fifty or sixty entities are sorting
out, and if more than a hundred are working on the problem, it starts to
get down to single digit frame rates. Still runs, though.

Further, stricter testing- 200 entities in a stack causes a severe but
survivable slowdown. A 400 entity stack slows the system down to
several-seconds-per-frame speeds during the sort step, though this does
noticeably recover when the entities spread back out, to the point of
basically becoming playable within the test arena.
Severe improvements to how the timer system and the move system handle
the new push action have improved performance of a lot of this stuff. A
push action is basically an override- if a push action is present in the
push system, it's now a push action.
And another one, just making sure that the push action override is
universal. Closing it down for tonight.
Merge branch 'master' of https://github.com/Somfin/DungeonFarmer.git