As reported by Angen:
- rP22314 moved SwapBuffers inside Render - this makes Atlas call it twice in a row which is possibly broken and certainly wasteful.
- rP22314 moved IdleTask from the sound manager outside of Render. I did not realise this would mean Atlas apparently never called it any more. Trough some weird fluke, it was called also in Game->Update but only in the specific path Atlas doesn't take.
Calling IdleTask every frame in Atlas fixes the sound issue stan reported, I think what happens there is that the buffers, being never cleaned, got overrun and new sounds couldn't start.
I'm not sure about the reports that we must only call IdleTask iff Render is called - needs some investigation.
I'm also not sure if we should call IdleTask when minimised, but I don't see why not as it would appear to be necessary for playlist and music doesn't stop when the application is minimised