working for circletest except for bullets sometimes skip over an element
circletest working with global physics timer
added while loop to reaction to ensure all collisions resolved each timestep, moved Collisions.list.push to element con constructor, and  circletest and polygontest working but not dronewar (yet)
dronewar working with latest code, moved some things around and added @destroyed property to @element class as well as some other new methods
renamed on to start, off to stop, start to start_physics, stop to stop_physics, activate to start_collision, deactivate to stop_collision, dronewar working, circletest working, rectangle collisions on polygontest not working
fixed polygontest bug by fixing while loop conditional and increasing max iter to 32 in elastic_collision, also made fang stronger in dronewar by increasing firing rate and bullet speed
recompiled dronewar and renamed a couple of variables for clarity e.g. dot1 = dot_a and dot2 = dot_b in reaction.coffee etc.
removed min size for quadtree ROI in collision.detect for improved computational efficiency (was using it for debugging and forgot to remove last commit)
merged two for loops in integration.integrate, renamed activate to collision, and fixed to physics
added @_cleanup=@_cleanup setter interface for element.cleanup
merged element.start with element.start_collision to simplify the binding to the physics engine and updated test games accordingly
updated dronewar to turn off fire timer in root element if destroyed
combined some loops over collision list into single loop by moving draw and cleanup into collision.detect