Game views refactoring

A little bit of code refactoring once again.

Several more or less Game-related views were always created and destroyed by ```Game```. Yet, they weren't part of ```Game```, but statics in ```Pi```. This PR changes this and is a preparation for moving the global ```Galaxy``` object into ```Game```, which I'm also working at, currently.

For a few views you could argue, whether they are really Game/Galaxy-related, but due to their lifetime and to keep the code regular, I chose to also move them to ```Game```. After all, even ```DeathView``` could be considered Game-related. One day. it could show your achievements in the game on the tombstone for example.

**Refactoring only**, every observable behaviour change would be totally unintended.