* Application::idle, physics and avatar processing are tracked
* Application::paintGL frameNumber payload is tracked
* OpenGLDisplayPlugin::present is profiled with corresponding frameNumber payload
* Added color and payload support to Nsight ProfileRange class.
Also, moved updateHeadPose so that the overlay and the main rendering use the same headPose.
Which should also be the same place the latencyMarker for the ovr_GetTrackingState is set.
Before this fix, a script could call into HMD.getHUDLookAtPosition2D() while the app was shutting down, which in turn would call
getHeadPose() on the currently active display plugin. This call could cause a crash within the openvr plugin, because the SDK was either shutdown, or in the process of shutting down on the main thread.
This fixes this by spliting the previous DisplayPlugin::getHeadPose(int) into two parts:
* updateHeadPose(int) which is only called once a frame and only by the main thread.
* getHeadPose() which is thread-safe and will return a cached copy of the hmd pose sampled by the last updateHeadPose.
* 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.
