Added simple tests covering the most basic cases for the query string parser.  Important to test as it defines the interface between the query string and the object list the library can use to decide which polyfills to include
Tests pass with this version.  Adding the service/helpers file and adding Mocha as a dev dependency
Include the gated flag for all polyfills if the query string parameter exists and is set to '1'.  This commit makes the API conform to the documentation, including a features query parameter