Player control methods

play_track()play current track
pause()pause the player
next()play next track - when tracklist's end is reached, pause on first track
previous()play previous track, if any - when tracklist's beginning is reached, pause
play_track(track_id)load and play a track, given its ID
play_playlist(playlist_id)load and play a playlist, given its ID
seek(seconds)set player position in current track (in seconds)
play_index()play a track in current tracklist using its index (0,1,2..) in the tracklist
is_playing()is player currently playing?
get_current_track_info()current track information (artist, title...)
get_current_track_id()current track ID