Fix handling anchors with nested elements

If an anchor contains nested elements (e.g. a span), onAnchorClick did
not handle the events that start on the nested elements.

Here is the jsfiddle for that case:
http://jsfiddle.net/sompylasar/QNQqN/3/

IE8 seems not supported by jsfiddle so open the raw result in IE8 to avoid unrelated errors:
http://jsfiddle.net/sompylasar/QNQqN/3/embedded/result/

Unfortunately, I could not include the latest version from GitHub directly, so I used the older one published at CDNJS.