We need to reduce the example run times for
testMRCA() in v0.2.5:
Examples with CPU or elapsed time > 10s user system elapsed plotMRCATest 16.10 0.02 16.11 testMRCA 14.73 0.00 14.73
Probably by redoing the algorithm. I think we don't need to redo the network search with each permutation. Instead, we can walk the graph once, store the node distances, and redetermine the MRCA from that info with each permutation.