Created MainScene to handle all the game
- background image with matrix (TODO: remove the "2" from background)
- onRightPress implemented as example for animation with callback
- Added class to build a number
- Added style for number "4"
- added Number class to buildup each number of the game
- added GameManage class to create numbers (this class should handle every move dispatch from the remote)
- added AppFonts
- added gameMatrix that stores the Number objects present in each position of the game matrix
- added print-out helper for dev/debug, showing he gameMatrix content

- added the number object to the gameMatrix for later reference when creating a Number
- added helper method that looks for a free cell in the gameMatrix randomly and returns the [row, col] position
- WIP: right press implementation, moving and joining numbers (join is currently crashing, check if it's overwrite of global vars)
- fixed crash when joining numbers (it was the dispose() of CoreElement trying to remove focus from Stage() when disposing a Number object)
- added Score and BestScore to be saved/retrieved from Registry
- added updateGameStatus after every move, checking for WIN or GAME OVER
- added moveLeft

getRandomFreeCell for new numbers HANGS the app after a few moves => review this method and change it to a quicker implementation to get a free cell