Preorder() provides a faster and simpler alternative, but also
rotates nodes.
Other tree manipulation:
AddTip(),
CollapseNode(),
ConsensusWithout(),
DropTip(),
EnforceOutgroup(),
ImposeConstraint(),
KeptPaths(),
KeptVerts(),
LeafLabelInterchange(),
MakeTreeBinary(),
RenumberTips(),
RenumberTree(),
RootTree(),
SortTree(),
Subtree(),
TrivialTree