Added a main menu and a collection

I added a main menu that can only do two things at the moment: bring you to the actual game and to the new card collection.

To fill up the collection will be the main goal of the game. You can win cards from opponents when you win a game against them.

Adding the collection and a deck of 5 cards from that collection was easier than I thought it was and so I had time to create a UI for the collection. I immediately had an idea for the design and approached it. Visually I was happy with the outcome, but to correctly display the cards and implement the different pages for the collection was a little bit challenging because there is (at least for my standards at the moment) much going on in the background.

The collection is generated at the beginning of the game and contains 3 cards: the caterpillar, the mouse and the snake. There are copies of them in the collection since they are weak cards. The deck is randomly build out of 5 cards from the collection, but the next step is to make a deckbuilder where you can choose the 5 cards you want and to actually win cards from opponents so you can start to fill up your collection ;)