GitLab

* src/ltlvisit/lbt.cc, src/ltlvisit/lbt.hh: New files.
* src/ltlvisit/Makefile.am: Add them.
* src/bin/common_output.cc, src/bin/common_output.hh: Add
support for LBT output, and reporting formulae that cannot
be output in this syntax.
* src/bin/ltlfilt.cc: Pass filename and linenum to
output_formula() for better error reporting.

* src/bin/common_cout.cc, src/bin/common_cout.hh: New files.
* src/bin/Makefile.am: Add them.
* src/bin/ltl2tgba.cc, src/bin/ltlfilt.cc, src/bin/common_output.cc:
Report error when writing to std::cout failed.  This is mainly
motivated by ltlfilt not being killed by SIGPIPE on lip6's OSX
buildfarm (SIGPIPE is probably ignored when the build is started), but
it could detect other errors such as a disk full.

* src/bin/common_output.cc, src/bin/common_output.hh: New file
with the common output code.
* src/bin/Makefile.am: Add them.
* src/bin/genltl.cc, src/bin/ltlfilt.cc: Simplify, using
argp's children parser, and calling output_formula().