Fixes for play() and stop().
Fixes for play() and stop().

Reading over the IOS docs, here are two updates:
 * play() should not call stop() because it unstages the sound for playback. In fact, we may want
   to add an IOS method for prepareForPlayback(), which reduces lag between calling player.Play()
   and when sound actually starts to issue forth.

 * stop() needs to set the current time on the player to zero explicitly to match the stop()
   contract laid down in PlayN Sound's stop() method docs.

playn/playn,playn/playn,thecocce/playn-1,rachelharvey/playn,thecocce/playn-1,rachelharvey/playn,playn/playn,tinkerstudent/playn,ruslansennov/playn2,ruslansennov/playn2,tinkerstudent/playn,longtaoge/playn,longtaoge/playn