"Reentrant" Mutex

[Mark B. Elrod]

I am rewriting the PlaylistManager to beef it up for 1.5. Lot's of cool
new things in this class... I seem to remember there being a problem (at
least under Solaris) with the old PlaylistManager re-entrantly calling
public functions protected by a mutex. Was this problem solved? If not
we need to solve it bc there are some major potential screw-ups that can
happen when multiple threads start calling some of the new functionality
I am adding.

elrod