…ill give get back some of the functionality that was lost when restricting gyro to same range as desktop by using wider range of tilt, and by setting a larger range of object motion. Also fixes the options handling in enable() so they aren't set every update, but only once.
Also ensures that starting position when using gyro is "in the middle", and not the position corresponding to the top left corner when using mouse.
This removes a lot of spaghetti code surrounding how we handled accelerometer support in Plax in favor of using the iPhone's gyroscope instead. This means we get a clean range-of-motion effect, much as if you were looking through a window at the object. Kind of. Sort of. This probably removes support for desktop (which I think is a good thing, since people tend not to move their laptops around), and potentially support for Android and weird devices like that. We can add that back in later. In general, though, I think this greatly increases the readability of the project and gives it an effect that makes a lot more sense.