Clean UI

• New Tiles type (updating comparison logic)
• UI Bug fixes
• Better code split

Better version

• Bug fixes (text centering; avoid Graphic2D NPEs)
• Customizable game (but hardcoded in a Config object)
• Better tile merging strategy
• Better code split

Test Version

This is the first version of this project:

• 2048 game that basically works as intended
• Written in Scala 2.13, with Cats 2.0.0
• Buggy Swing GUI (I feel so clumsy with Swing)
  -> too long to boot
  -> strange Board scaling after first move
• Game board State, stored in a mutable Variable (ewww...)