Add RemoteControlReceiver to handle MediaButton events, the implementation is TODO.
Implement audio focus and handling media buttons.
Fix an issue that pause() cancels the audioFocusListener, it causes the service unable to receive AUDIOFOCUS_Gain message;
Fix the pauseButton image in paused state.
When losing audio focus, do not let pause() cancels the audioFocusListener; otherwise, still let it cancel.
Use ACTION_AUDIO_BECOMING_NOISY instead of HEADSET_PLUG to better pause the playback.
Handle multiple clicks on headset key:
press once: pause/play
press twice: next
press three time: prev
more: ignore
Fix issue-39, sexypsf crash if lib does not exist for minipsf files.
Merge branch 'DEV_remote_control'
Merge branch 'issue-39'