* Removed MyAvatar.reset() access from JavaScript
* Added HMD.centerUI() to JavaScript, which can be used to reset the 3D UI sphere around the current HMD orientation.
* Added MyAvatar.clearIKJOintLimitHistory() which can be used to reset any remembered IK joint limit history.
* Added MyAvatar.centerBody() which can be used to instantly re-orient the avatar's so that the hips and toes
are facing the same direction as the current HMD orientation.
away.js now uses the above new API's instead of MyAvatar.reset()
