Implements basic pile changing of cards, no rules enforced yet.
- Fixes problems with card changing piles.
- Makes cards autoreveal when they become the top of the tableu.
- Every revealed card is now draggable.
Implements autopopping cards from the stock when a card is taken from the waste.
Merge pull request #14 from ofirpicazo/drop-card

Implements changing a card from piles. Closes #15