Forth

This is the beginning of a Forth interpreter in Python, written just to learn a little bit about Forth.

There's still more to do and some of the fundamentals may have to change if it turns out some missing feature of Forth is not implementable the way I've currently done things.

One thing I am proud of, though, is the way Python functions are turned into their equivalent operating on a stack.

Suggestions welcome, though, especially for expanding coverage of Forth.