Combining graphics and text in one stencil?

[Mark Polesky]

I'm able to write my own graphical stencils using
ly:make-stencil, and I also can override stencils with
text or markup using the ly:text-interface::print
callback, but now I want to make one stencil with
graphics *and* text, and I can't figure out how to do
that.

Is there some way to achieve something akin to this:
(ly:make-stencil (list 'string "foo"))

That would be my preference.

I experimented with
(ly:make-stencil (list 'char ...))

but I couldn't get it to do anything.  output-ps.scm is
very difficult to follow with no docstrings.  Ugh.  Any 
advice is appreciated.

Thanks.
- Mark