COFC tuning and mouse rotation tweak

Some tuning to the zoom behaviours of COFC (particularly in tiltzoom), and rotation with mouse now rotates around a point in the world rather than the camera rotating FPS-style. I'll be modifying the options later to allow a choice between mouse behaviours in a radio-button format of "Rotate Camera, Orbit Camera/Rotate World, and Pan Camera", which will be both for vertical and horizontal separately