Sign in and authentication model rework

Right now, I need to build an image on a device, then take that device's androiddebugkey and put it on the Google Calendar API credentials page. Then, you gotta log into the account on the device, enter the calendar key, and it _ought_ to work. The issue with this approach is that I think my apk will only work with _my_ calendar. This is problematic for a number of reasons.