Some Python built-in functions are not implemented

[danieltanfh95]

Functions like complex(), help(), dir(), divmod(), hash(), map() are unavailable. Haven't tested all of them though.

[differentmatt]

There are quite a few that haven't been implemented yet. The list in README.md should be fairly accurate.

I would love some input on which ones are more and less important, so we can implement them in the correct order.

[danieltanfh95]

:P Missed those. Personally, zip() and set(), along with slices (basically data structure functions and methods) are the ones that I think are important to implement first.