[Ecls-list] Immediate short-float for ECL

[Lars Brinkhoff]

[Resend.  Note: this is just for review and discussion.  I will keep
working to remove test failures, etc.  There are also some stray fixes
unrelated to floats in this patch.]

Here's a preview of my patch which adds an immediate short-float type,
temporarily called SI::IMMEDIATE-SHORT-FLOAT, to ECL.  It's not 100%
complete yet, and there are test regressions, but I believe most
things work.

Code size growth is minimal.  Before:

   text    data     bss     dec     hex filename
   1977     324       8    2309     905 ecl-cvs-20060929-orig/build/bin/ecl
1293505   43932   65984 1403421  156a1d ecl-cvs-20060929-orig/build/libecl.so
 436221    3312     256  439789   6b5ed ecl-cvs-20060929-orig/build/cmp.fas

After:

   text    data     bss     dec     hex filename
   1992     324       8    2324     914 ecl-cvs-20060929-isf/build/bin/ecl
1297769   43964   65984 1407717  157ae5 ecl-cvs-20060929-isf/build/libecl.so
 436812    3312     256  440380   6b83c ecl-cvs-20060929-isf/build/cmp.fas

http://lars.nocrew.org/tmp/ecl-cvs-20060929-isf.diff