Display multiple phylogenies

[gaurav]

This PR is a place for working on displaying multiple phyloreferences on a single phylogeny. It also implements some changes to how we display phyloreferences that resolve to a tip.

This works in both the display:

As well as the Nexus file, as displayed in FigTree:

But there are a few issues:

• Neither FigTree nor our display clearly indicates that two phyloreferences have resolved to the same node (both Crocodylidae and Crocodyloidae resolve to the Crocodylidae node on the phylogeny). We should modify the Nexus export to ensure that we support this fully.
• We currently draw a small circle on the Crocodylinae node because we put circles on all the nodes (as is the default for Phylotree.js) -- could that be confusing?

[gaurav]

• Turn phylorefs into links -- when you click on them, open the phyloref from the sidebar. (not simple to do, so I've moved it into Make phyloreferences within phylogenies clickable if there is more than one of them #334)

[gaurav]

• Nothing wrong or misrepresented, but it can be misconstrued that this clade is only one node -- when really there is a whole clade back there.
• For branch-based, we do want to highlight the entire branch up to the previous node. (This would be nice, but not a priority)
• For node-based, we don't want to do this.
• Reserve italics for either phyloreferences or internal labels without clade names.
• Change the internal node labels so they're in the same font as the terminal labels -- this will indicate that they come from the same place.
• For the individual phyloreference, don't display the internal label, but rather the phyloreference. Displaying the internal node labels for the summary makes more sense, but don't use font/weight/italics to distinguish them from the others, because otherwise people will wonder why they're different and whether they're coming from the same place.
• Use hover-over to show the phylorefs resolving to that node.

[gaurav]

• Visualizing multiple phylorefs on a single node or edge in Nexus goes beyond phyloreferencing.

[gaurav]

• For branch-based phyloreference, we could add a symbol to the clade, and then add a note underneath the phylogeny to say that this is clade extends up the parent branch.
  • Note that qualifiers can render a node-based clade into a branch-based clade, so we might want to look for "maximum" or other text in the definition.