Log Message:
Update R-bnlearn to version 3.1. Major changes:

* fixed all.equal(), it did not work as expected on networks
  that were idetical save for the order of nodes or arcs.
* added a "moral" argument to cpdag() and vstructs() to make
  those functions follow the different definitions of v-structure.
* added support for graphs with 1 and 2 nodes.
* fixed cpquery() handling of TRUE (this time for real).
* handle more corner cases in dsep().
* added a BIC method for bn and bn.fit objects.
* added the semiparametric tests from Tsamardinos & Borboudakis
  (thanks Maxime Gasse).
* added posterior probabilities to the predictions for
  {naive,tree}.bayes() models.
* fixed buffer overflow in rbn() for discrete data.