Adding VR support with IK

[Livb-VRC]

It'd would be extremely useful for avatar creators(or world builders that somehow involve complex ik) if you could emulate the way vrchat does IK so you can use an avatar in unity and for example playing around in real time with avatar proportions for a better fit

[CyanLaser]

VRChat uses Final IK for their avatar IK system, which is a paid asset. While I eventually will have a form of IK system with avatars, this project is open source and I will not be distributing a paid assets with it. Whatever IK I create will not match VRChat's exactly but probably be just enough to get by. Also, this project is intended for world testing. At this time, I do not intend for it to also include avatar testing.