Auspice 2.39.0

• A range of improvements to the measurements panel including reference sera coloring
  and more informative tooltips. See PR 1557 for more.
• Color-by genotype dropdown: nuc (nucleotide) is now the first item in the list.
  See PR 1550 for more.
• Fixed a bug where zooming out one level would instead jump multiple levels.
  See PR 1552 for more.
• Added a toggle to force the display of all branch labels, rather than only those meeting
  a certain threshold. See PR 1554 for more.
• Install documentation updated. See PR 1551 for more.