Until we can fix it properly (or replace it with a cleaner event
system), I don't want this in trunk.  Currently there are
strange pauses when queueing and during shutdown that I can't
seem to figure out right away.

git-svn-id: https://svn.musicpd.org/mpd/trunk@6860 09075e82-0dd4-0310-85a5-a0d7c8717e4f