Support new Anki package format

[kerrickstaley]

Anki seems to have a new package format. Now, when I extract a .apkg, I see the files collection.anki2, collection.anki21, and media. This collection.anki21 is a new file. Like collection.anki2, it is a SQLite 3 database, and it seems to have roughly the same schema as collection.anki2. I'm guessing it's related to the Anki 2.1 scheduler update.

Presumably, importing Anki 2.0 packages will still work for a long time, so this isn't urgent.

[yash-fn]

Does he specify anywhere what the exact differences are? Or does one have to manually inspect his codebase to determine what is happening?