Return a tree with the ID of a node altered.
Details
IDs cannot be changed directly for the TreeMan class. To change an
ID use this function. Warning: all IDs must be unique, avoid spaces in IDs and only
use letters, numbers and underscores.
Use updateSlts after running.
Examples
tree <- randTree(10)
tree <- setNdID(tree, "t1", "heffalump")
tree <- updateSlts(tree)
