clade labels suppress amino acid labels

[rneher]

When labeling branches with amino acids, these labels don't show on branches with clade labels. see branches at which clades changes. Most have aa changes, but they don't show.

https://nextstrain.org/flu/seasonal/h1n1pdm/ha/6y?branchLabel=aa

[jameshadfield]

This issue is a bit complicated, so i'll try to explain what's going on:

Firstly, there is a difference in the JSON between aa labels and AA mutations. Auspice is designed to display the former, but not the latter. Augur isn't exporting the labels correctly, e.g. in h1n1pdm / ha / 6y.

                          "labels": {
                            "clade": "6b"
                          },
                          "mutations": {
                            "HA1": [
                              "K163Q",
                              "A256T"
                            ],

Here's the bug in tha augur code: https://github.com/nextstrain/augur/blob/master/augur/export_v2.py#L529. I'll add a PR ASAP.

---

Secondly, there is an issue with auspice, which I've fixed (PR soon). We currently have this code to decide what labels to display, as to display them all isn't good:

As we add more labels other than just clade / aa, this is not ideal. I'll create a PR ASAP to propose we:
(a) Display all label values by default, unless the labeling is aa (see screenshot above)
(b) for aa labels, display them if the branch has any other labels, or if it meets the current threshold.