* 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/Makefile.am, src/taalgos/dotty.cc,
src/taalgos/emptinessta.cc, src/taalgos/minimize.cc,
src/taalgos/minimize.hh, src/taalgos/tgba2ta.cc, src/taalgos/tgba2ta.hh,
src/tgbatest/ltl2tgba.cc: changes introduced to add a new form of TA
called GTA (Generalized Testing Automata). GTA is a TA with acceptance-
conditions added on transitions.