tweaking mp3 player
sound container view inserts as desired now
each mp3 view knows about its own sound model now
individual sound play buttons now add that sound onto the global playlist, and play it from there
mp3player views create SM sounds, playlists are all collections, and each mp3 view holds onto its own SM sound AND BB sound now
current sound properties turned into functions to avoid superfluous attr setting; also sounds play from global playlist and keep track of themselves just fine
players track sounds, and shading works again
shading only applies to one mp3 view now