src/tgbaalgos/emptiness.cc (emptiness_check::safe): New method.
* src/tgbaalgos/magic.cc, src/tgbaalgos/magic.hh,
src/tgbaalgos/se05.hh, src/tgbaalgos/se05.cc: Implement it.
* src/tgbatest/randtgba.cc: Simplify.