Expand co-publication network to have accurate publications for individual PIs

[risserlin]

When constructing a co-publication network we search for all the pairs of authors in the literature and then look at just the queries in a subnetwork of the resulting network. Graphs created as just based on the co-pub stats. Would be nice to have a function that will query pubmed for just the individual nodes in the sub-graph and calculate their publications over-time and citations over-time that is not dependent on the co-pub publication but instead reflect the individual PI.