Sum Improvements

I'm here to notify you that bunch of commits has finally formed the patch to be released.

The Good:

- Fullscreen mode is now properly supported (except for fps counter placement, which will be fixed later). You can also play with screen resolution values in settings.toml (but settings these to non-16:9 aspect ratio may render things weird).

- Game Over menu now has button to restart the game.

- Main menu now feature a placeholder of logo.

- Many under-the-hood changes.

The Bad:

- There is a known bug that may cause segfault on scene switch. Working on that.

- There is also a known bug that may cause settings corruption. May be the part of other bug, investigating that.

Footnotes:

Next update should mark major changes in build process for windows - instead of mingw, game will be compiled with visual studio.

Why is this important? Because I still have no machine to test windows builds on, thus people may encounter some errors related to missing libraries. Hopefully this will be reported asap.