* moved all settings from SQLite to SharedPreferences. The database now contains only dictionaries.
* removed key remapping, dictionary backup and nuke functions along with a bunch of unused code and translations
* slightly optimized candidate scrolling animation
* added missing Russian translations
* the soft keys fit properly on the screen
* central soft key is now always 'OK', because users do not care about the exact functions it performs in the code
* removed 'mode notify'; it wasn't working on Android 11 anyway
* removed 'space on 0' option; 0 is always 'space' now
* disallowed global key remapping and removed the app setting
