Fixed some issues brought by the new content of chess variants. For example..
-A couple of the variants didn't work. I tested the variants more to make sure that they work.
-White 2d Rook+Rook piece had wrong graphics, it didn't have the same look as all the other pieces.
-Pawn+Pawn piece was able to jump through pieces if it was on the 2nd rank (for white) or 7th rank (for black). (Pawn+Pawn piece couldn't be found from those places before the added chess variants).