Set element order changed in Clojure 1.6 (hashing logic?) so our tests needed to be updated.
Library updates and Clojure 1.6 testing.

* core.incubator 0.1.2 -> 0.1.3
* data.json 0.2.1 -> 0.2.4
* mongo-java-driver 2.10.1 -> 2.11.4
* clojure 1.4.0 -> 1.5.1 (default version)
* tests against 1.3.0, 1.4.0, 1.5.1, 1.6.0-beta1