computed-observable breaks when depending on more than one derefed CO

[oskarth]

;; works
(def a (atom 0))
(def b (computed-observable (inc @a)))
(def c (computed-observable (dec @a)))
(def d (computed-observable (str @b)))

;; doesn't work 
;; In the chrome console: Uncaught RangeError: Maximum call stack size exceeded
(def a (atom 0))
(def b (computed-observable (inc @a)))
(def c (computed-observable (dec @a)))
(def d (computed-observable [@b @c]))

Using Clojurescript 0.0-1450, lein-cljsbuild 0.2.7 and reflex 0.1.1.