Code cleanup in ODApplication and ODFrameListener.cpp/h files.

Along with the usual code cleanups, I made the renderer destructed within the framelistener
where it is created, stopped using members for a few singletons, and remove one
duplicate reference to the root scenenode used there.

I also moved the movable entity update code within the corresponding class,
which permitted a few simplifications.
Simplified the frame listener initialization by moving render manager component back to it.