I discovered that drawable.py already had a put_pil_image
very much like the one in Circus, so I changed xss_colorsquares.py
to call that one directly; this cut the import list in half, and
simplified the rest of the code as well.
Also started on xss_base.py which is a generic xscreensaver
base class, and xss_chbg.py which is an instantiation that
is a cheap clone of the chbg desktop cycler I use - none of the
transitions or fades, just chewing through a list of files. They're
both still in flux, though.