OpenVR SDK 1.14.15

New events:

• VREvent_DesktopViewUpdating
• VREvent_DesktopViewReady

IVRDriverDirectModeComponent:

• Updated CreateSwapTextureSet to (optionally) allow NTHandle support

IVRServerDriverHost:

• Added SetDisplayProjectionRaw
• Added SetRecommendedRenderTargetSize
• Renamed TrackedDeviceDisplayTransformUpdated -> SetDisplayEyeToHead

[git-p4: depot-paths = "//vr/steamvr/sdk_release/": change = 6100641]