Code Review for Job #19831

Code Review for Job #19831 - Workitem available at https://www.worklist.net/19831
As I said it is probably necessary for certain things (which means that if we don't add it now we'll get feature requests for it until we do), so adding MyAvatar.setVelocity() is fine.  Eventually we'll have other ways to move the avatar and people will be able to use them instead.