Replace github/concoR with CRAN/concorR library

The referenced [concoR library on github](https://github.com/aslez/concoR) is from 2015 and hasn't been updated since; there is now a [concorR](https://cran.r-project.org/web/packages/concorR/index.html) (note spelling) package on CRAN, with Carter Butts (sna) as one of the authors. We should use this instead. It will involve a little code rewriting, as the functions and parameters are different.