COMMON: Move ownership of the depth stencil buffer and viewport to child classes

Since the children are the ones that modify them now. DepthStencil is also an object
of Common::Depth2D now instead of directly being a ID3DTexture2D
DEFERRED_SHADING_DEMO: Disable MSAA

It serves no purpose in deferred
DEFERRED_SHADING_DEMO: Change the title bar caption
DEFERRED_SHADING_DEMO: Create a pixel shader for deferred shading
DEFERRED_SHADING_DEMO: Create GBuffer logic
DEFERRED_SHADING_DEMO: Use the new pixel shader
DEFERRED_SHADING_DEMO: Render the GBuffers to the sceen
DEFERRED_SHADING_DEMO: Set the specular power to 1.0

Since in the gbuffer it acts like the alpha channel.
TODO: Create shaders to specifically render the gbuffers instead of using
the sprite renderer