Step through historic turns

[lkingsford]

Add Left, Right, Begin and End buttons
Use log, updating visual state
Don't show choosables

[lkingsford]

So - there's been lots of progress on this, but there's a fundamental issue with boardgame.io with phase changes. I've made a bug report on boardgameio/boardgame.io#923

I don't know how long that will take to fix, so I'm investigating whether I can remove the phases from the game (knowing that it'll make the structure a bit uglier)