Parser doesn't recognize double quote escapes in strings.

[Idorobots]

1 | "hurr\"durr"
2 | ;run
;; repl(1,7): Undefined variable `durr`, did you mean `cadr`:
;;   1 | "hurr\"durr"
;;     |        ^^^^
;;   2 | 
;; repl(1,11): Unterminated string literal, expected a closing `"` to follow:
;;   1 | "hurr\"durr"
;;     |            ^
;;   2 | 

The PEG rules for strings are very simple right now and need an update.