Lots of changes.

See CHANGES.rst
A few more little changes.

- Decks now store their cards in a deque.
- Fixed some formatting that bugged me.
- Added the method Deck.set_cards, to set a decks contents to a
different list of cards.

See CHANGES.rst.
Fixed a couple little things.

Fixed a couple of small things in the changelog and readme.
Pep8 fixes and fix traling spaces