* src/tgba/acc.cc, src/tgba/acc.hh: Add a way to extract
an unstatisfiable mark, and fix the eval() function for
Fin acceptance.
* src/tgbaalgos/complete.cc: Label the sink state using
an unsatisfiable mark. Do not assume generalized Büchi.
* src/tgbatest/complete.test: New test.
* src/tgbatest/Makefile.am: Add it.
