Version 2.2.0

See #127.

User facing

• Improved homefeed
• Include all Minerva notifications
• Improve UI for Minerva notifications
• Improved Urgent.fm tab (see #124)
• Show Snackbar when using offline cached data
• Fix crashes
• Data saving options for home feed
• Open Schamper in Chrome Custom Tab, as the mobile site is pretty good now. This is a better experience, and reduces maintenance for us: Schamper can do what they want now, we don't have to keep track and update the code.

Behind the scenes

• Introduce basic tests
• Fix lots of crashes
• Improve home feed algorithms
• Fix lots of memory leaks
• Move to Jack compiler; this enables use of lambda's and method references (see https://developer.android.com/guide/platform/j8-jack.html)
• Use lots of lambda's and streams 👍
• Move code around
• Use string resources and remove a lot of hard coded strings (#72)