Add ClojureScript support (using cljc)

[nberger]

Alternative version of #14, with bump to clojure 1.7.0 to use reader conditionals.

Status

• [x] test.chuck.properties
• [x] test.chuck.generators (except double & regexes)
• [x] test.chuck.clojure-test
• [x] Implement a better test runner to avoid calling (run-tests) in each cljs test ns, and also to run tests in the browser.
• [x] Improve lein test-all (and/or add a new "test" alias) to compensate the issue of leiningen not picking up .cljc files. The namespaces have to be explicitly enumerated. See technomancy/leiningen#1940

[nberger]

Just pushed the rebased commits.

I kept 7 commits, not just 1, as I think it might be of value to keep those separate in the history. But let me know if you think we should squash some or all of them.

[nberger]

@gfredericks I just updated test.check dependency to 0.8.2

Let me know if you find anything else :)