* src/ta/ta.cc, src/ta/ta.hh, src/ta/taexplicit.cc,
src/ta/taexplicit.hh, src/ta/taproduct.cc,src/ta/taproduct.hh,
src/taalgos/dotty.cc, src/taalgos/emptinessta.cc,
src/taalgos/emptinessta.hh, src/taalgos/minimize.cc,
src/taalgos/reachiter.cc, src/taalgos/sba2ta.cc, src/taalgos/sba2ta.hh,
src/tgbatest/ltl2ta.test, src/tgbatest/ltl2tgba.cc: Impacts of the
implementation of a new variant of TA, called STA, which involve a
Single-pass emptiness check. The new options (-in and -lv) added to
build the new variants of TA allow to add two artificial states:
1- an initial artificial state to have an unique initial state (-in)
2- a livelock artificial state which has no successors in order to
obtain the new form of TA which requires only a Single-pass emptiness-
check: STA (-lv).
* src/ta/taproduct.hh, src/ta/taproduct.cc: improvement of TA Product
* src/ltltest/randltl.cc: improvement of WFair Formulas generation
* src/taalgos/minimize.cc: improvement of TA minimization
* src/taalgos/minimize.hh, src/taalgos/minimize.cc: implements a
minimization of TA by merging bisimular states.
* src/taalgos/statessetbuilder.hh, src/taalgos/statessetbuilder.cc:
returns the set of reachable states of a TA (used in minimize.cc).
* src/taalgos/Makefile.am: add them.
* src/tgbatest/ltl2tgba.cc: add commands to test TA minimization
