Add Clojure 1.6 support (cljs tests failing)

@cpetzold @loganlinn, whoever else

The Clojure side works fine in 1.6, but the cljs tests do this:

```
Performing task 'test' with profile(s): 'dev,1.6'
Running all ClojureScript tests.
ReferenceError: Can't find variable: cemerick

  target/unit-test.js:27923
ReferenceError: Can't find variable: cemerick

  phantomjs://webpage.evaluate():2
  phantomjs://webpage.evaluate():5
  phantomjs://webpage.evaluate():5
ReferenceError: Can't find variable: cemerick

  phantomjs://webpage.evaluate():2
  phantomjs://webpage.evaluate():5
  phantomjs://webpage.evaluate():5
Error encountered performing task 'test' with profile(s): 'dev,1.6'
Subprocess failed
```

Any ideas what's going on?  Not sure if this is a real issue or I've just messed up the profiles.