Wrote the card class and started the deck class.
Implemented initialization and shuffling of single-symbol decks.
Added drawing cards from the deck.
Added the deckGroup class with default starting values and a dictionary of deck colors.
Added methods to draw cards from a deck group given a list of colors.
Proper indexing for pet diet.
Fixed up drawing multiple cards from a deck group.
Added discarding cards.
Merge branch 'dev'