Regexs are munged

[snoe]

A bug in clojurescript causes forward slashes / anywhere in a file to get munged to \/.

This actually breaks user code so I think in the short term we should extend IPrintWithWriter and hack around the slash issue. I briefly looked into fixing the core issue but there are many more corner cases around translating javascript regex output back to a cljs regex.

A transform-test case:

(deftest testing-regex
  (are [i j] (= i j)
       "(re-find #\".*//foo.com/x\" foo)"

       (pr-str
        '(re-find #".*\/\/foo.com\/x" foo))))