Add name-spaces to the clojure koans files.

This pull request is essentially a duplicate of #69 but without the eclipse specific entries.
In order for this to work without causing failure of koan test then functional-koans/clojure-koan-engine#9
needs to be merged into the koan-engine project.

Note that this strategy may help in some use cases but it does not solve the issue mentioned in #68
(though I really wished it did).