Fix path strings: prepend with 'lib'
Fix Hash check to use global namespace

Using `is_a?(Hash)` inside a custom class called `Hash` does not yield intended
results, specifically checking against the global Ruby hash type. Prepending the
global namespace identifier `::` fixes the issue.
Begin adding test cases

Using rspec to write test cases. I just happen to be most familiar, and
therefore comfortable, with it at the moment.