S40 release

[dr.mt...@gmail.com]

I've been working with Shen and an upcoming release S40.  The basic changes are

1.  Incorporate coder's suggestions for fixing 'syntax error here' messages.  I have to look at those.

2.  Redistribute code in the sources files to make the work of Yggdrasil easier.  This does not involve changing code, but changing the location.

3.   Introduce a small but useful change wrt absolute and relative pathnames.  At the moment the cd command works without exception.  Sometimes though it is useful to exempt a file name from being relativised.  Shen/Tk experienced this problem, losing sight of the files through which communication is funneled.  These paths need to be invariant wrt cd.

The architecture of Shen is actually very compact so there is a one line change in open which will do the trick.  

(DEFUN open (String Direction)
  (LET ((Path (IF (MEMBER String *absolute*)
                             String
                             (FORMAT NIL "~A~A" *home-directory* String))))
       (cl.openh Path Direction)))

I'll add two system functions absolute and unabsolute which will add and remove paths from the global.  I generally avoid messing with primitives, but this is the simplest fix.

Mark