"ltl2tgba -Rm" will apply WDBA-minimization only if correct.
* src/tgbatest/ltl2tgba.cc (main): Use WDBA-minimization only when it is correct. Either we can quickly determine that a formula or its negation is a safety formula, or we can slowly check the equivalence of the WDBA-minimized automaton and the original automaton. * src/tgbatest/wdba.test: New test. * src/tgbatest/safety.test: Adjust comment. * src/tgbatest/spotlbtt.test: Use -Rm. * src/tgbatest/Makefile.am (TESTS): Add wdba.test.