[Nauty] Nauty version 2.7 + Traces 2.2 release candidate 2 available

[Brendan McKay]

The second release candidate of nauty 2.7+traces 2.2 is available at the 
usual places:
     http://users.cecs.anu.edu.au/~bdm/nauty/
     http://pallini.di.uniroma1.it/

Since the first release candidate there have been some small technical
improvements (not bug fixes) invisible to users, plus these changes:

* Some portability issues in nautycliquer.c were fixed (thanks to Isuru 
Fernando).
* More information is provided to PRUNE/PREPRUNE plugins of geng.
* listg -qb  (Bliss output) suppresses the "c" (comment) line.

Our intention is to make 2.7 the official release within a few weeks, 
after that
subject only to bug fixes.  Further enhancements will occur in betas of 
version 2.8.

Please let us know of any problems you know of.

Brendan and Adolfo.