Added back button and refactored the PlanningPokerSessionTab
Back buttons works and more refactoring
Merge pull request #34 from TheTeam8s/feature-backbutton

Feature backbutton
Added a deck class which extends abstract model
added a function to convert numbers in the deck to a string containing the numbers
Add in deckEntityManager methods
Add comments and remove unnecessary code
Add more deck entity manager methods and deck methods
Added deckListModel for keeping track of decks
Adds deck field to planning poker session and adds methods to Deck model
Added name field for decks and auto-incrementing ID method in the deck entity manager
Add autoname method to deck class and make method to create default deck with fibonacci numbers
If deck is added to the list of decks without a name, autoname it to have the name of Deck [id number]
Add default deck when DeckListModel is created
Add AddDeckController to save decks
worked on AddDeckController
Added AddDeckRequestObserver
Add dropdown options for deck including default and none
Add methods to AddDeckRequestObserver
Add getDeck controllers and observers