Work on unifying function interface and allowing optional/rest args

I don't know exactally what I did as I wrote it yesterday, but that's
the gist of it
Merge branch 'master' of github.com:hitchiker42/SciLisp
resolved conflicts between commits from different computers
Conflicts:
	Makefile
	cons.h
	eval.c
	frontend.c
	lex.yy.c
	lex.yy.h
	prim.h
	print.c