This adds support for parsing the new index-v1.json data as defined in
fdroidserver!221. This new index metadata format is required to
support localization, graphics, screenshots, etc.
refs #15
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
