[Icecast] Crossfader for ices 0.3

[Brendan Cully]

FYI, I've added a crossfader to the ices0 trunk in subversion:
http://svn.xiph.org/icecast/trunk/ices0

It requires LAME support (of course). To use it, either pass -C <secs>
on the command line, or add a <Crossfade>secs</Crossfade> node to the
Playlist section of the config file. Reencoding must also be enabled
on your stream.

NOTE: the crossfader can't resample, so all of your input files should
be the same sample rate.

I'd appreciate feedback from anyone who is comfortable compiling from
subversion (nightly tarballs won't be back until some issues with the
xiph.org servers have been sorted out). Hopefully I can release ices
0.4 soon, if no issues surface.

Thanks,
-b