Change REST route used for loading program grid from TV Media to AJPGS

[mkahn-optv]

Currently using a call in TVMediaAPI.js from AJPGSPollingService. Add a new class, AJPGSAPI.js and put the appropriate grid fetching call in there. Then modify AJPGSPollingService.js to use that call instead of the direct TVMedia call and test. Work with Ryan to make sure you are using the right endpoint.