lbtt: take options as a string like other print functions

* src/twaalgos/lbtt.hh (print_lbtt): Take a const char* opt argument.
* src/twaalgos/lbtt.cc: Use it, select state-based
vs. transition-based using automaton property, and implement output
for generalized state-based acceptance.
* src/bin/common_aoutput.cc, src/bin/common_aoutput.hh,
src/bin/dstar2tgba.cc: Adjust usage.  We do not need to handle
--lbtt=t as a special case anymore.
* src/tests/lbttparse.test, wrap/python/spot.py,
wrap/python/tests/automata-io.ipynb, wrap/python/tests/piperead.ipynb:
Adjust.

src/tests/lbttparse.test

@@ -27,7 +27,11 @@ do
   # Make sure Spot can read the LBTT it produces
   run 0 ../../bin/ltl2tgba --lbtt "$f" > out
   s=`wc -l < out`
-  head -n 1 out | grep t
+  if ../../bin/ltl2tgba -H "$f" | grep 'properties:.*state-acc'; then
+      head -n 1 out | grep t && exit 1
+  else
+      head -n 1 out | grep t
+  fi
   run 0 ../../bin/autfilt --lbtt out > out2
   s2=`wc -l < out2`
   test "$s" -eq "$s2"