Fixed improved parsing

I had to abandon the idea of having a closure that recursively calls
itself pop tokens off a token iterator because apparnently you can't do
that kind of recursion in rust. Now I'm passing around a vec and
.shift()-ing, which is O(n) and bad, but there must be a rust Deque
which solves this problem. Still I'd like to know why I can't get the
pointers right to make an iterator work.
Added 'run' directive to Makefile
Parse NumLiteral correctly
Add support for quoting