Ancestral state reconstruction function

[ScottClaessens]

Not a priority, but it would be nice to have a function that plots ancestral state reconstructions for a given trait. We could do this on the latent scale (as in our NHB paper) and/or on the observation scale.

[ErikRingen]

Yep, I was also thinking this and had some scrap-paper code version of this for a while when I was working on the manuscript. I found it was actually very straightforward because of the way we arrange the tree segments: the eta indices should line up exactly with the nodes of the tree.

[ScottClaessens]

Yes, exactly. We can also use the code from the authority paper for this. I think this isn't something we should try to get done for the initial release though.