Fix flippedness bug drawing vertical 3 part images.

Fixes #77

Rebel/RBLResizableImage.m

@@ -135,7 +135,7 @@
 		NSDrawThreePartImage(dstRect, leftEdge, center, rightEdge, NO, op, alpha, flipped);
 	} else {
 		// Vertical three-part image.
-		NSDrawThreePartImage(dstRect, topEdge, center, bottomEdge, YES, op, alpha, flipped);
+		NSDrawThreePartImage(dstRect, (flipped ? bottomEdge : topEdge), center, (flipped ? topEdge : bottomEdge), YES, op, alpha, flipped);
 	}
 }