The Kana Quiz v0.13

Enhanced the multiple choice answer selection with a category system
Added vocabulary questions, with kanji, and an option to choose how they're displayed
Can now copy to clipboard any item on the reference screen with a long press
Added a line graph to the log view to show progress over time
Added a link on the About screen to the new privacy policy
Reference screen now displays a message if there are no items
Corrected spelling of the word 'romaji'

New pure build contains only open-source code, with Firebase and Crashlytics removed, replaced with ACRA crash reporting