Volumetric
The "Unknown touch device" message appears because the initial touch device setup loop uses SDL_GetTouch() as a guard for calling SDL_AddTouch(). SDL_GetTouch() will always report "Unknown touch device" since the device hasn't been added yet. The SDL_GetTouch() call is unnecessary since SDL_AddTouch() calls SDL_GetTouchIndex() to verify that the device hasn't been added yet, and SDL_GetTouchIndex() has the benefit of not reporting an error for a device it can't find.
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.
