More work on the lexer, specifically arrays, added new lisp_array struct
and worked on strings/unicode a bit

I also modified the lisp_string type, Strings are going to be a union of
const char*'s, const wchar_t*'s and CORDS, because CORD's really are the
best way of dealing with builting and concatenating strings, but for
most other purposes (especally indexing I imagine) regular  c
strings (with a known constant length) are better.

Oh and I also wrote the lexing routines for package accessing, though I
have no way to make packages yet.