Now that we have a nice background service, let's put it to work! This
makes update APKs be automatically downloaded after the index is updated.
Then when the user goes to install the updates, they will not have to wait
for the download part.
#601https://gitlab.com/fdroid/fdroidclient/issues/601
This makes it a lot easier to setup all the testing stuff. Mostly,
I'm tired of fighting Android Studio's fragility, so I want to remove
as much non-standardness as possible in the hopes of improving that
situation.
closes#534https://gitlab.com/fdroid/fdroidclient/issues/534
