Statistics on past card reviews

[LRudL]

This plugin is almost exactly what I need to switch from Anki to something better. However, a really nice thing about Anki is the statistics window. This plugin implements a lot of it (showing the forecast, intervals, eases, card types, etc.), but is missing what I see as the most important part: tracking how many cards you have studied in the past. This is really great for monitoring streaks, setting a habit, and knowing how much time you're spending on spaced repetition. This also seems easy to implement.