See pull request
Underlying framework changes. Moved to AndroidX, and removed Material Dialogs. Replaced with SimpleDialogFragments. Removed JCenter references.
Added Dark Theme. By default it will follow the system mode (if the system is in dark mode, or battery saver, the app will get dark theme). It's also possible to manually set dark theme via the General Settings screen.
Reworked preferences screen. The preferences, most of them, will now show the value that the user has selected. The 'summary' moves into the dialogs where there are edit text preferences.