A object of class phylo but where each branch length is
equal to the marginal shift odds on each branch.
Details
This function returns a copy of a phylogenetic tree where each
branch length is equal to the marginal odds ratio in favor of a rate
shift on a particular branch. These cannot be interpreted as evidence
for a rate shift in an absolute sense. As explained on the website,
they are a marginal odds ratio. This function is provided primarily
for the purpose of distinguishing core and non-core shifts.