Bug Fixes. Updated docs and lib.

* fixed an issue with Sound.removeSound not stopping audio with that src.
* fixed an issue with pause and setPosition on audio files that are not looping, which would generate an error in WebAudioPlugin.
* fixed a bug with WebAudioPlugin that stopped SoundInstances from being reusable.
Updated Tutorials. Simplified directory structure.

Signed-off-by: Lanny McNie <lanny@gskinner.com>