New games:
- Echo: repeat the coloured pads, one more each round
Bug fixes:
- Spider and Klondike cards drag without lag
- The menu fits a phone on its side
- Coins can no longer be spent on a broken price
Improvements:
- Checkers: Huevo Style rules, thanks to @HuevosKicker
- Chess and Chinese chess: face to face for two players
- Pool and Snooker: pull the cue stick back to shoot
- Sudoku boxes clearer in the dark theme only
