Add 2 benchmarks directories.
Add an algorithm to split an automaton in several automata. * bench/scc-stats: New directory. Contains input files and test program for computing statistics. * bench/split-product: New directory. Contains test program for synchronised product on splitted automata. * bench/split-product/models: New directory. Contains Promela files and LTL formulae that should be verified by the models. * src/tgba/tgbafromfile.cc, src/tgba/tgbafromfile.hh: New files. Small class to avoid long initializations with numerous constants when translating to TGBA many LTL formulae from a given file. * src/tgbaalgos/cutscc.cc, src/tgbaalgos/cutscc.hh: New file. From a single automaton, create, at most, X sub automata. * src/tgbaalgos/scc.cc, src/tgbaalgos/scc.hh: Adjust to compute self-loops count.