pygame.mixer.music play music with start position

[ProfessorDragon]

Currently pygame.mixer.music.play ignores the start and fade_ms arguments.

It should be easy to implement start by adding this line to the existing MM.play function:

track.media.currentTime = start;

fade_ms would be more difficult, it would require something like a setTimeout loop which manually adjusts the media's volume. pygme.mixer.music.fadeout should mimic the behavior of fade_ms but in reverse.