Subtree and subnetwork extraction #29
Description
Given a subset of taxa S, return the subnetwork restriction to this taxon set. Additionally, this feature should allow the restriction to the same subset for all of the gene trees associated with the species network.
The key issue/tricky part here is how to resolve reticulations after subsetting. I believe it is best to have support for 2 options: (1) keep all reticulations that have at least one extant descendant, and (2) prune out "undetectable" reticulations.