Removed view transformers from OpenGLSystem
Enhanced views in OpenGLSystem

Views are now a stack based approach. This allows them to be pushed and
pop for different cameras.

Additionally View() has been renamed to GetView()
Cleaned up OpenGLSystem

Formatting changes mainly.

Also added some error checking to OpenGLSystem::Start() to check for
various features before attempting to use them.
Fixed the issue with creating a FPSCamera

Also fixed mouse look in FPSCamera, I had the x and y swapped.

Also fixed an issue with the aspect ratio math and rounding.