can't run convert-ly.py under WinME in version 2.5.31

[Brynne and Russ Jorgensen]

Is a python interpreter supposed to be part of the lilypond distribution 
on windows?  If so, I couldn't figure out what it was called, so I 
resorted to my cygwin version of python to run convert-ly.py...

Not all of the necessary .py files are included in the windows 
distribution.  I copied lilylib.py, fontextract.py and convertrules.py 
from the lilypond source distribution into lilypond/usr/bin to get 
things working temporarily.  It looks like they are supposed to go 
somewhere else, but the code at the top of convert-ly.py that figures 
out datadir looks like it might need some modifications for windows use.

        -Russ