Provides simple physics functionality for tweening an object's x and y coordinates (or "left" and "top") based on a combination of velocity, angle, gravity, acceleration, accelerationAngle, and/or friction. It is not intended to replace a full-blown physics engine and does not offer collision detection, but serves as a way to easily create interesting physics-based effects with the GreenSock animation platform. Parameters are not intended to be dynamically updateable, but one unique conveni