Sync to breaking SFML changes: Scoped Keyboard enum

[x] Unfortunately, this affects SFW, too, and then the entire static lib build chain, of course.
[x] Keyboard::Key::... (https://github.com/SFML/SFML/commit/39da2b829caeea3c07d36b8e290ce05872538623)
[x] Window::create has a new arg. for sf::State::Fullscreen
[x] sf::Cursor::Arrow -> sf::Cursor::Type::Arrow etc.
[x] sf::Mouse::Left -> sf::Mouse::Button::Left etc.

Time to target pinned SFML versions in the builds!

xparq / Out_of_Nothing