Refactors Game Object
First stage of #18.
- GameObject converted to GameObjectComponent and ComponentLocator< GameObjectComponent > typdefed to GameObject.
- Scene now takes care of managing game object components, functions within the GameObject class simply defer to Scene.

Also:
A bunch of headers got rearranged to make the new system work. One advantage of this is that Gunship.h now contains everything needed to make a game,
so game code only needs to do #include <Gunship.h> and it will have access to all of gunship.