Improve shuffling

[leafyscreen]

The shuffle algorithm needs improving.

1. When the deck is empty and it reshuffles, you get the exact same hand you just had.

2. When you get 2 of the same card, they often come up together after the next shuffle.

3. Too many times cards seem to be stuck together and you keep getting them together in future hands.

4. Often when you get a card and the deck is shuffled, that card shows up in the first hand after the shuffle.

5. It almost seems like the cards stay in the same order and hands are modified only because cards are added.