Replace prxml with clojure.data.xml

Hi,

I have replaced the redundant prxml with clojure.data.xml, which is compatible with clojure 1.4 and above.

Therefore I have upgraded clojure to 1.4, and refreshed other dependencies.

All tests pass and have tried with a live server and is working as expected.

This should also address the Issue I raised earlier today around the dynamic var errors.

cheers

Christian