Improve the parser

[deosjr]

Short-term goal: to be able to use quote and quasiquote properly, on atoms and on lists.
Currently quotes are hacked in and only work in simple terms.
Pretty sure that the current way of dealing with strings doesn't survive any serious QA efforts :)

Longer-term goal: an overhaul of the parser, support for read macros.
Reading from a file stream instead of taking it all into memory first.
Comments that terminate at end of line instead of only having multiline.

[deosjr]

Short-term goal achieved in #12
Also overhauls the parser somewhat already