%s stays in tooltip if there is no series label

[lmacko]

I think it would be better if it were removed. So there is no need to change content option in tooltipOptions. If there is series label %s is replaced and if not only x,y coordinate is show.
It's just two lines

else{
            //remove seriesPattern if label is not defined
            content = content.replace(seriesPattern, "");
        }