Add and remove cards

Probably adds methods to decks to change the contents of decks.
addCard(self, str) adds the card named str to the deck or increments the
number of said card.  removeCard(self, str) removes all instances of the
card with name str from the deck.
setNumCard and removeCard fix

setNumCard(self, str, num) is a Deck method that sets the number of the
card named str to num multiplicity.