Rewrite the ltl2tgba bench using ltlcross
* bench/ltl2tgba/sum.py: New file. * bench/ltl2tgba/.gitignore, bench/ltl2tgba/Makefile.am, bench/ltl2tgba/README, bench/ltl2tgba/algorithms, bench/ltl2tgba/big, bench/ltl2tgba/defs.in, bench/ltl2tgba/known, bench/ltl2tgba/small: Rewrite this benchmark completely. Also drop support of Wring and Modella, as we cannot get them to work reliably. * bench/ltl2tgba/formulae.ltl: Rewrite in Spot's syntax. * bench/ltl2tgba/lbtt2csv.pl, bench/ltl2tgba/ltl2baw.in, bench/ltl2tgba/parseout.pl: Delete these scripts, no longer needed. * configure.ac: Do not output ltl2baw.pl anymore.