* src/bin/common_output.cc: Add option --format and implement
it.
* src/bin/ltlfilt.cc, src/bin/randltl.cc: Document the
supported %-sequences.
* src/bin/genltl.cc: Document the %-sequences, and supply
the name of the pattern to output_formula().
* doc/org/genltl.org, doc/org/ioltl.org, doc/org/ltlfilt.org,
NEWS: Document it.
* src/ltltest/latex.test: Use it.
* src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh
(to_latex_string): New function.
* src/bin/common_output.cc, src/bin/common_output.hh:
Add a --latex option.
* doc/tl/spotltl.sty: New file.
* doc/tl/Makefile.am: Distribute it.
* src/ltltest/latex.test: New test.
* src/ltltest/Makefile.am: Add it.
* NEWS: Mention it.
