Fixed memory leak in Quit due to changes related to background thread removal. FreeData was quick escaping because it checked for ALmixer_Initialized which is now false by the time the code is reached. Code was refactored to introduce an Internal_FreeData which skips this check. Also, I think there is another 'bug' where I should actually be able to delete buffers even though the context is NULL as long as there is a device. But this is all really ugly corner case stuff.