0.8.17.3809 - Quick T-pose full body calibration

- Added quick full body T-Pose calibration, which allows quickly mapping trackers by posing in a reference and pressing both triggers
-- This is now the first calibration step for the full body calibrator, with the adjustments serving to fine tune the calibration
- Added AvatarPoseRotationConstraint, which allows constraining the orientation of a body node (limiting swing and twist around an axis)


- "Reset Mapping" on Full Body Calibrator now just recalculates the default avatar calibration, rather than disabling it (this would break avatar body anchors)
- Full body calibrator now has basic instructions displayed on the top
- Light Orb Tip will now spawn light in the current local space of the user, rather than global
- Updated default SteamVR bindings of Oculus Touch controllers. This should fix some symmetrical bindings not working correctly (like touching X/A buttons, reported by @Hayden )
- Changed default render distance to 4096
- Upgraded to Unity 2019.2.7f2 (from 2019.2.6f1)


- Prevented avatar from being grabbed when entering or leaving fullbody avatar calibration, preventing it from being re-equipped
- Fixed filling of empty slots on avatar (spawning default hands/head) from dequipping just equipped avatar in some cases - this should fix the full body calibrator sometimes dropping user out of their avatar and leaving them without voice (encountered by @Nexulan , @pikapetey and others, please let me know if this bug still happens!)
- Fixed being able to anchor user to avatar anchor that's part of their hierarchy (e.g. being held or being on another user anchored to them) (reported by @Shifty )
- Fixed avatar anchors incorrectly unparent objects when the target space is not part of the anchor
- Fixed friends dialog trying to update message UI that has been removed in the meanwhile
- Added guard for invalid number of read samples from and audio source
- Fixed rare exception when updating online status, due to accessing uninitialized user instance
- Fixed labels for avatar calibration references in the full body calibrator being too small or too large for certain avatars
- Fixed exceptions when playing looped OGG audio clips causing audio issues and heavy performance (discovered thanks to log from @LeonClement )
- Fixed not being able to set unregistered user as a target for the interactive camera