Components

I refactored the PhysModel into a PhysComp. I did this because I feel like components are a better way to work with stuff like this compared to inheritance. This is also partly because this is the way that Unity does it, and I know that it works well there. The only significant difference for the rest of the group is that a PhysComp needs to be created for each physics object, and they need to access the component with GetPhysComp().

Similarly collisions are now handled by a Collider component, for essentially the same reasons listed above. Most of the game object does not need to interact with the collider. A collider will need access to its parent though, so the constructor for a Collider will pass down a pointer of the parent object to store for that.