Transparency woooo!
Change folder names, and implement basic Box2D debug drawing.

Rename the Subsystems folder to Services.
Rename the DirectX folder do D3D11.
Implement Polygon class to draw polygons.
Implement b2DebugDraw class for drawing Box2D debug data.
Add two boxes to the world, one static and one dynamic. The dynamic one falls
onto the static one and bounces.
Implement IndexBuffer and interface.
Implement VertexBuffer and interface.
Implement only one Vertex type.
Change some method names across the codebase.
Add casts to Vec2 and Vec3 classes to cast them between one another.

	NOTE: if casting from Vec3 to Vec2, the Z component is discarded.