Namespace fixes in *test.clj files

Updated multi-word *test.clj files to use valid clojure namespaces in
function calls.

Also updated namespace declarations in the following files:
crypto_square_test.clj
difference_of_squares_test.clj
largest_series_product_test.clj
robot_simulator_test.clj
Merge pull request #18 from bjarnagin/master

Namespace fixes in multi-word *test.clj files