Issue reported at http://www.opentk.com/node/3805
We must not throw exceptions from a finalizer, as this leads to the
runtime forcibly taking down the application.
Moved SoundData and SoundFormat to OpenTK.Compatibility.
Moved AL and Alc classes to OpenTK.Audio.OpenAL and added the previous namespace to OpenTK.Compatibility.
Removed SoundData wrappers from AL class.
Updated samples to use the new API.