fixed dolist and made do much eaiser to use

something like for(i=0;i<n;i++) in common-lisp would be
(do (i 0 1 (< i n))) in SciLisp before it would be
(do (i (setq i 0) (setq i (++ i)) (< i n))) whereas now it's
(do (i 0 (++ i) (< i n))) so yeah, much nicer syntax, and the cool thing
about it was how I do it, I really just rewrite the new version into the
old version internally, which you can only really do in lisp.

Also I fixed dolist, which I don't think I had ever reallly finished
writing in the first place