Resolve label link styling and event structure

[kkoreilly]

[rcoreilly]

make a LabelLinks struct, put Stylers, Listeners in it, and be done with it. it really doesn't need a full Widget object per link, right?

[kkoreilly]

There are significant issues with just doing that: the event manager needs to be aware of the labels and handle long hover events at that point; otherwise, it is impossible to trigger long hover events at the right time. Also, the tooltips created for links do not get cleared correctly. Also, even if you have style objects for each link, it is unclear how to pass them to the renderer, as we hand over links to paint immediately.

[kkoreilly]

One option for this is to have a real widget that doesn't render anything overlayed for each link in the appropriate position.