Procedural Animation

Adds procdeduralAnimationAPI.js, which provides some basic functionality for constructing procedural animations.

Adds bot_procedural.js, which runs a bot that implements a procedural walk animation with smooth blending. It also shows varying facial expressions dependent on a random mood, it plays random audio clips via the avatar, and it plays footstep sounds.

Exposes a few more things to the JS including Quat.slerp and Quat.squad, and allows the scripts to change head yaw and roll.