Make tests pass

Hi, I forked the repo and found that tests are not working. I suppose there was a convention change (from  `underscore_method_names` to `camelCaseNotation`) so tests were broken. I made the following changes:
1. Updated the tests to make them pass.
2. Removed PHP 5.2. from travis config. Because namespaces are used, there is no way to support PHP 5.2, I suppose.