This implements the ILP solution of network orientation from the paper Network orientation via shortest paths.
This takes a mixed graph as its interactome, which is a headerless .tsv containing
the source, node, direction ∈ {U, D}, and weight ∈ [0, ∞).
This also takes in a sources file and a targets file, both formatted as a newline-separated list of nodes to act as sources and targets for network orientation.