Add Bifurcator Chess

Add Bifurcator Chess

A self-concocted Chess variant using the concept of bifurcating
pieces conceived by Mats Winther. The Bishop and Rook are replaced
by upgraded versions that have all usual moves, but 'bounce off' the
first friendly piece that would have normally blocked them. They can
continue at 45-degree angle on either side of that piece. This seems
good to drive anyone crazy! Piece values as yet completely unknown,
but obviously higher than the usual B and R, as they get lots of extra
moves when the board is well populated, so I upped them 1 Pawn.