v206 typescript updates
- several minor documentation clarifications/updates, including some links off to the 'learn' site
- HorizonReferencProprety now documented to be... about something w.r.t. copy() and clone() safety? Still seems unused in the api. Ignore?
- OnPassiveInstanceCameraCreated now documented to be abount a 'service-based player camera' that doesn't use the processing power of the end user device. No more info than that
- new Camera.setCameraModeFollow()
- follows and auto-turns to be behind the player avatar
- new FollowCameraOptions
- things like activationDelay, cameraTurnSpeed, continuousRotation, distance, horizonLevelling, verticalOffset, translationSpeed, and rotationSpeed
