Adds Rules::ResponseFunction.

This callback will be issued for events in an object's event queue.
Adds response rules to Registry::Rule.

Rule classes hold the response functions that they will attach to an
object as part of the rule's behavior.
Adds event queue to World::Object.

This queue will, once per frame, be resolved by any attached
Rules::ResponseFunction stored in the object's RuleSet.
Adds ResponseFunction to win32 build filters.
Adds ResponseFunction query methods to Registry::Rule.
Makes all geometry functions and computations use floats.

Floats are faster and generally better supported on graphics hardware.
We will probably want to eventually do these computations on the gpu,
and our object data and representations will be floats... so we should
get used to it.