New formats: Cube Draft, Booster Draft, Sealed, and Vintage

Play limited? Cube Draft, Booster Draft, and Sealed are now supported as formats — no set pool or banlist since you build from whatever you open, just a label to tag your decks and matches with for stats. Vintage also joined the official constructed formats. Formats are now grouped under "Constructed" and "Limited" wherever you pick one, so the two don't get mixed together in one long list.