Implemented the ability to make directed pairs from pairs of persons.

social-net-functions:
-Persons who already exist can be put in a list of lists, where each sublist is a directed pair in the form (SPEAKER LISTENER).  LISTENER gets put in a new group, and SPEAKER gets a link to that group in 'TALKS-TO.   (Behavior of MAKE-UNGROUPED-DIRECTED-PAIRS)

make-dirpairs-model:
-makes 6 people and a pundit who talks to everyone.  The 6 get directed links, then the pundit gets 5 ticks to talk.  After that, the pundit is silenced.
Adding smart grouping functionality.
Annoyances:  returns NIL, and I'm not sure why...  I thought it should be returning the 'TALKS-TO for each SPEAKER, just like the ungrouped function.