Yuya Hanai

As of natnet v2.10, mean marker error is always set to positive, so RigidBody::isActive() is not working right now. The issue is fixed by utilizing tracking valid flag.

…ct for 09x

- I merged your latest commit with @madelinegannon 's great IMU, recording class. - Fixed multi example to get correct external sync Still some APIs are messy, but working.