Fixed a number of small bugs causing runtime issues.  Removed a circular dependency with workunits, renamed SetGravity on the physics manager to SetWorldGravity, updated logic for notifying a world object a proxy is being destroyed, added a check for parent validity in the ray query tool.
Fixed a bug that was prevent transforms from syncronizing between proxies.
Fixed more runtime bugs in EngineDemo.  Collision flags weren't being defaulted properly, Scaling in Collidable proxies weren't being defaulted properly, both of these were preventing collisions.  Checked pointer validity when creating collision reports.  Minor touchups of EngineDemo code.
More script binding updates.
Merge branch 'master' of https://github.com/BlackToppStudios/Mezzanine