Generate IK for your own local character

[philpax]

To generate IK, we will need to use an IK algorithm. Probably the dev branch of https://github.com/TheComet/ik. This will give us a pose for the joints we solve for, and then we will need to apply those to characters.

Potential points of concern:

• whether or not the selected library is ready for "production" use
• finding and applying the relevant constraints for a body
• gracefully degrading when full-body tracking data is not available
• gracefully degrading when tracking is lost
• avoiding self-occlusion
• creating believable results in real-time
• determining user limb lengths
  • could potentially be handled by an external program (LÖVR?)