Feature Requests: Rewind phases

I think it would be really nice and make this awesome app a little better and a little more sandboxy, especially for testing decks, to add a true back/undo button when going through phases of a turn. Ive had a lot of issues, especially with learning the ins and outs, with skipping past my second main phase in particular or accidently tapping for mana, thinking I could play something that I couldnt and then going to a different phase only to have all of my tapped mana go away.