Token objects and start_pos for everything

This is not yet finished, actually it just started. I opened this for discussion.

1. I realized that having a Token class for every token-type means quite a lot of classes. I think I can be done fast, but is it useful? It would need a hashlookup or a if else tree for creation.
2. If not I would create Token(object) and TokenLiteral(Token)

More comments in the code...