* bin/common_setup.cc, bin/common_setup.hh: Define a protected_main()
function that deal with exceptions.
* bin/autcross.cc, bin/autfilt.cc, bin/dstar2tgba.cc, bin/genaut.cc,
bin/genltl.cc, bin/ltl2tgba.cc, bin/ltl2tgta.cc, bin/ltlcross.cc,
bin/ltldo.cc, bin/ltlfilt.cc, bin/ltlgrind.cc, bin/ltlsynt.cc,
bin/randaut.cc, bin/randltl.cc: Use it for all tools.