* AUTHORS: Add Thibaud.
* NEWS: Mention ltlgrind and ltlcross --grind.
* src/ltlvisit/mutation.hh, src/ltlvisit/mutation.cc:
Use an enum instead of #define.  Rename get_mutations()
into mutate().  Other minor cosmetic changes.
* src/bin/ltlgrind.cc: Adjust.
* src/bin/ltlcross.cc: Slight changes the the output
* doc/org/ltlcross.org, doc/org/ltlgrind.org: Minor
rewordings and fix for org-mode syntax.
* src/ltltest/ltlcrossgrind.test,
src/ltltest/ltlgrind.test: Fix copyright year.