[R6RS] new syntax srfi draft, reference implementation

[dyb at cs.indiana.edu]

I have committed a new syntax srfi draft and a reference implementation:

  srfi/syntax/syntax.html (also srfi/syntax/syntax.pdf)
  srfi/syntax/implementation/syntax.ss (reference implementation source)
  srfi/syntax/implementation/syntax.pp (reference implementation expanded)
  
In the new draft, I've tried to address all of the questions and comments
I have received,

I have not yet inserted a formal operational semantics, although the text
description of the operational semantics is now much more detailed.

I have flushed literal-identifier=?, which confused Mike, and reverted to
free-identifier=? for matching of identifier literals but may have more
to say about this later.

Kent