Refactoring

[Sesu8642]

Here are some things that I would like to refactor at some point:

• the UI, especially the ingame screen hast too much logic which should go somewhere else, e.g. determining whether the winner changed during a bot turn
• texts should be in some resource file (translatable later)
• the complexity of some methods is way too high and they should be split up
• autosaving needs be more efficient and save less data (there are performance problems on huge maps)
• the event bus is a little overused which causes very (too) loose coupling at some places
  • the loose coupling makes sense between frontend and backend as well as internally in the UI
• there should be way more unit tests
• visibility of many classes and methods is too high
  • could be limited to package but I like to use packages for organizing the structure too much
  • maybe Java 9 modules could help but the project is stuck with 8 for now
  • json serialization/deserialization using the libGDX API is tedious and relies on hardcoded package names
    • better use Jackson or Gson as GWT compatibility is no longer relevant