Merge pull request #694 from smklinger/patch-2

CCTiledMapLayer.m issues #687 & #693

Author: slembcke

cocos2d/CCTiledMapLayer.m

@@ -117,7 +117,7 @@ -(id) initWithTilesetInfo:(CCTiledMapTilesetInfo*)tilesetInfo layerInfo:(CCTiled
 		_mapTileSize = mapInfo.tileSize;
 		_layerOrientation = mapInfo.orientation;
 
-		CGFloat pixelsToPoints = 1.0/tex.contentScale;
+		CGFloat pixelsToPoints = tex ? 1.0/tex.contentScale : 1.0;
 
 		// offset (after layer orientation is set);
 		CGPoint offset = [self calculateLayerOffset:layerInfo.offset];