GetClosest              Get the closest taxon to the focal taxon
GetClosestSamples       Get n samples
GetEnclosingTaxonomy    Get enclosing taxonomy for a feasible tree
GetSimilarity           Get similarity Uses ape's cophenetic.phylo to
                        get patristic distances between pairs of taxa,
                        then makes the diagonals Inf. If the tree has
                        no branch lengths, makes every edge length 1.
LabelNodesWithChosenDescendants
                        Include descendant taxon ids in node labels
LabelNodesWithFeasibleDescendants
                        Include descendant taxon ids in node labels
SubsampleTree           Return a sampled tree
