playsound updates.

[Ryan C. Gordon]

I've made some FIXME cleanups and commandline handling improvements to
playsound. In the process, a lot of code got moved around, so please let
me know if anything stops working out of the blue; it's probably my fault.

(It compiles, but I'm ona dumb terminal, so I wouldn't know if I ruined
playback entirely...sorry to make you all guinea pigs, but I'm out of town
and soundcardless.  :)  )

--ryan.