Fixed tooltips not showing in browsers not supporting css animations.

In browsers where css animations is not supported (in this case IE9/IE8) the tooltips does not get shown at all. This seems to be because we're always adding the animation class to the created tooltip element and since the default animation is "fade" we get a tooltip that is caught in a permanent state of

opacity: 0;

I've fixed this by only appending the animation class to the created tooltip element if the browser supports animations. This seems to work properly for me. :)