Returns an pull parser useful for walking through token streams.
var p = steal.parse(" steal.dev.log('fo(') ");
//parses until it finds thing(
p.until( [ "thing", "(" ] );
//parse until it finds the matching ) to (
p.partner("(");
steal.parse(str) -> steal.parse
{String}
{steal.parse}
an object that can be used to pull tokens.