[R6RS] new library srfi draft

[dyb at cs.indiana.edu]

I've committed a new library srfi draft to srfi/library/library.html (or
srfi/library/library.pdf).  All are welcome to look at it, but this
version is primarily intended for Matthew so that he can go over the
numerous changes in syntax, phasing, and eval support.

I have not yet tried to create an updated reference implementation, but as
I mentioned last week, I intend to incorporate libraries into the existing
syntax-case reference implementation and also to give Andre van Tonder a
chance to do the same with his syntax-case implementation.

Kent