Feature request: Differentiate click on box label from box body

[meself001]

From my experience with this library so far, I can't seem to differentiate between a nodeClick event between one done on the node label (HTML class "title-group") or the main body (HTML class "body-group"). It would be really useful to us to expose this detail as we'd like to redirect (as per solved issue #7) only if the label is clicked.

Thanks.