Remove Board Overlay

[jlnrrg]

It is possible to add boards, but when I miss-clicked, I have to start all over again, bc there is no remove board functionality.
Implementation wise, I'd say a Minus Overlay over the boards would do the deed.

[adri326]

I can add this as a third mode (totalling Add boards, Add pieces and Remove boards). Until then, you can remove the relevant 5DFEN entry from the editor

[jlnrrg]

I like that you choose to include it as a separate mode. This creates a security barrier to not delete boards by chance, while adding boards.