[CM] On FFI bindings

[bil at ccrma.Stanford.EDU]

I agree it's a good idea -- I have it working (I hope)
in my current version of s7 -- need to test it more, but
it should be in the repositories by tomorrow.

On the name, I've think
the "_" names are less likely to collide with other names
in the environment, and maybe emphasize that they are just
connections to C (dlopen and dlsym).  Also while rapidly
reading code, I don't notice the difference between "_"
and "-" (much worse is "1" vs "l"), even when wearing
piano glasses.