Find the crossing points of an epoch-time with each lineage of a tree

Find the crossing points of an epoch-time with each lineage of a tree

PCMTreeLocateEpochOnBranches(tree, epoch)

Arguments

tree	a phylo
epoch	a positive numeric indicating tip-ward distance from the root

Value

a named list with an integer vector element "nodes" denoting the ending nodes for each branch crossing epoch and numeric vector element "positions" denoting the root-ward offset from each node in nodes.