some small bugfixes

some small bugfixes

I had overlooked one place from which the FEN writer (of whicf I changed the argument types), which made WB crash if you copied a FEN (or PGN that cotained FEN) to the clipboard. I must have overlooked a warning during compile, or some depedency is not correct in the makefile. Anyway, wclipboard.c had to be changed.

I also moved adjudication of some losing conditions to before tetsing for stalemate, (e.g. in atomic, if your king get destroyd you lose, even if you have no moves after that because it was your only piece.). this affects backend.c.

I had used the same bits in the frule-modifier flags for indicating mandatory capture as was already used for indicating FRC-style castling. This led to frequent illegal move calls in FRC... (moves.h)