HALFLING: Remove unused file
COMMON: Add a class to animate lights
DEFERRED_SHADING_DEMO: Animate the point lights in the scene
DEFERRED_SHADING_DEMO: Revert back to a fullscreen vertex shader that requires no geometry input

It's significantly faster since no information is streamed to the gpu.
DEFERRED_SHADING_DEMO: Add Shaders for rendering simple, instanced, debug geometry
COMMON: Update Model class to allow instancing
DEFERRED_SHADING_DEMO: Render instanced spheres at the center of each point light