Handle window resize

[tim-we]

Once the game has started and you resize the window the game area does not change. That is fine but I think after a round ends / before a new one starts the game area should be resized.

[maechler]

@tim-we Thanks for your feedback! You are absolutely right, this would be a nice addition. I wanted to avoid that someone could mess with the window size and kill an opponent that way. At the time it seemed the easiest way to implement it like this. However your recommended approach should not be too difficult either, I will have a look at it.

[maechler]

@tim-we I implemented this and released a new version!

[tim-we]

Awesome, thanks!