IVROverlay:
* Added GetOverlayKey and GetOverlayName which return the key or name of an overlay from its handle.
* Added GetOverlayImageData which returns the current raw image data from an overlay.
* Improved reliability of SetOverlayRaw and SetOverlayFromFile.
* Added VREvent_ImageLoaded, which is sent when SetOverlayRaw or SetOverlayFromFile finish updating the overlay texture.
* Added VROverlayError_UnableToLoadFile, which may be returned if SetOverlayFromFile fails.
* Added ShowDashboard, which will make the dashboard visible if a dashboard manager is present. We arent shipping a dashboard manager quite yet, so this function currently does nothing.
IVRNotifications:
* This new interface allows applications to post notifications to the user. Details and documentation are coming soon.
[git-p4: depot-paths = "//vr/steamvr/sdk_release/": change = 2877976]
22 files changed
