perf: Deck inits faster, inherits from Iterator
refactor: Deck's internal items now use 'index' instead of 'id'
feat: Deck now implements ES6 iterator protocol
test: Deck's iterator methods
fix: JSON.dry & .undry correctly handle root objects
test: JSON.dry & .undry unit tests
feat: Deck#toDry and .unDry now work with the new structure
test: Deck#toDry and Deck.unDry tests