Updated to V2.2

Most part are bugfixes, especially with the checkmate check. Another interesting update is the kinda new invitation system. You now get a popup if you get invited and you can actually decline the invitation. But the script now also checks if your opponent has the script loaded.

And last but not least, you can now easily re-select a piece by just clicking on it (instead of unselecting the old piece first).

V2.3:
Bugfixes it now shows the last move (which causes checkmate), and some other small bugs.