* src/bin/autfilt.cc: Add these new options.
* src/tgbaalgos/stutterize.cc, src/tgbaalgos/stutterize.hh: Make it
possible to call sl() and sl2() without passing the set of atomic
propositions.
* src/tgbatest/stutter.test: New file.
* src/tgbatest/Makefile.am: Add it.