need String type

[john-science]

I need to support the Python str type.

I think most of the work to do this will be in parser.py. I imagine this will complicate the regex I use to split the code into AST. I don't want spaces inside of a string to be counted as list separators.

[john-science]

Okay, I have implemented a basic string type. But... I have no built-in helper functions. Surely a string needs some basic functionality?

string_append, string_split