refactored away preprocess function
fixed bug expanding ''()
Changed interupt handling: ^C interupts current evaluation, ^D exits REPL
removed broken quote tick expansion
Merge branch 'master' of github.com:kvalle/moo-lisp
fixed expression formatting for 'Expected EOF' error
fixed quote tick expansion
added parsing of quasiquote/unquote
evaluation of quasiquote/unquote
added let expressions to language
fixed bug with unparsing empty list/nil
added (help) texts for quoting and let expressions
improved errors in REPL
rewrote parser