Update deps

This updates the Leiningen Clojure and JRuby deps to 1.5.1 and 1.7.10 respectively. It also updates the Clojure jar used for testing. All tests (lein test & rspec) still pass.

Also, just a thought, but it might be simpler to curl the required [Clojure version](http://repo1.maven.org/maven2/org/clojure/clojure/1.5.1/clojure-1.5.1.zip) during a test preparation task rather than include it in the repo.