Another pacakge name change.

One does not simply "experiment" with the Android developer console. Once published to Alpha, u no get test apk expansion files. Anymore. Ever :)

New package name and back to Draft it is, so we can test properly.
Update public key and expansion file version.

Download is now working, except for callbacks to download UI.
Reasonably working expansion file downloader.

Still have one issue (#13: Cannot resume expansion file download sometimes) however there's a reasonable workaround (at least for Alpha status), so committing what we have since this is getting mind-numbing.