[CM] S7 wrapper around SDL

[bil at ccrma.Stanford.EDU]

That's an interesting project!  I don't know anything
about SDL, so I can't offer any sage advice.  On the
matrix library, there's also the libgsl stuff in the
s7 tarball.  If you're writing the matrix functions in Scheme
and notice anything that seems unnaturally slow,
please let me know.  Good Luck with SDL/OpenGL (I was
pleased to see openGL in use!)