Pass a InputCalibrationData to each inputPlugin and inputDevice.
This contains the most up sensorToWorldMatrix, avatarMat and hmdSensorMatrix.
Each input plugin can use this data to transform it's poses into Avatar space
before sending it up the chain.
This fixes a bug in the handControllerGrab.js script that relied on the hand controller
rotation/positions being in the avatar frame.
* Call vr::VR_Shutdown() when ref-count goes to zero. The ref-count
is ncessary because the vr::IVRSystem poitner is shared between the
the openvr input and display plugins.
* OpenVR plugins options will display in the menu if vr::VR_IsHmdPresent() is true.
This is faster then initializing all of openvr and less likely to conflict with the
oculus display plugin.
