Fix a long running potential bug when file changes are handled by the editor.
A small optimization to the file watcher.
Optimizations for scene nodes that use convex hulls for collision.

This is still work in progress. Lots of work to go here.
Some improvements and optimizations to the way OnChanged() is posted from components.

The changes introduced with this commit are mostly centered around the idea that
when OnChanged() is posted, a set of flags are passed with it that specify what it
is that actually changed. This way we can more easily only update things that
actually need updating.
Merge branch 'master' of https://github.com/mackron/GTGameEngine
Editor: Fix an few issues where prefabs are being unnecessarily updated during the transition of playback states.
Fix a bug in the files watcher.
Fix an issue where OnKeyReleased and OnKeyDown are not getting posted correctly when the window loses focus.
Improved the way component panels are updated in the editor when a scene node is updated.

This fixes a bug where the keyboard focus would be removed from a text box when the scene node was updated.
Update CHANGES.
Add ability to control scene node transformation inheritance via the scripting environment.
Stop being lazy when updating the script component panel in the scene editor.
Update CHANGES.
Scene Editor: More intelligently place new scene nodes as they're inserted into the scene.