Use 'const formula*' instead of 'formula*' everywhere.
The distinction makes no sense since Spot 0.5, where we switched from
mutable furmulae to immutable formulae. The difference between
const_visitor and visitor made no sense either. They have been merged
into one: visitor.
* iface/dve2/dve2check.cc, iface/gspn/ltlgspn.cc,
src/eltlparse/eltlparse.yy, src/eltlparse/public.hh,
src/evtgbatest/ltl2evtgba.cc, src/kripkeparse/kripkeparse.yy,
src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/automatop.cc, src/ltlast/automatop.hh, src/ltlast/binop.cc,
src/ltlast/binop.hh, src/ltlast/bunop.cc, src/ltlast/bunop.hh,
src/ltlast/constant.cc, src/ltlast/constant.hh, src/ltlast/formula.cc,
src/ltlast/formula.hh, src/ltlast/formula_tree.cc,
src/ltlast/formula_tree.hh, src/ltlast/multop.cc,
src/ltlast/multop.hh, src/ltlast/predecl.hh, src/ltlast/refformula.cc,
src/ltlast/refformula.hh, src/ltlast/unop.cc, src/ltlast/unop.hh,
src/ltlast/visitor.hh, src/ltlenv/declenv.cc, src/ltlenv/declenv.hh,
src/ltlenv/defaultenv.cc, src/ltlenv/defaultenv.hh,
src/ltlenv/environment.hh, src/ltlparse/ltlfile.cc,
src/ltlparse/ltlfile.hh, src/ltlparse/ltlparse.yy,
src/ltlparse/public.hh, src/ltltest/consterm.cc,
src/ltltest/equals.cc, src/ltltest/genltl.cc, src/ltltest/kind.cc,
src/ltltest/length.cc, src/ltltest/randltl.cc, src/ltltest/readltl.cc,
src/ltltest/reduc.cc, src/ltltest/syntimpl.cc,
src/ltltest/tostring.cc, src/ltlvisit/apcollect.cc,
src/ltlvisit/apcollect.hh, src/ltlvisit/clone.cc,
src/ltlvisit/clone.hh, src/ltlvisit/contain.cc,
src/ltlvisit/contain.hh, src/ltlvisit/dotty.cc,
src/ltlvisit/length.cc, src/ltlvisit/lunabbrev.cc,
src/ltlvisit/lunabbrev.hh, src/ltlvisit/mark.cc, src/ltlvisit/mark.hh,
src/ltlvisit/nenoform.cc, src/ltlvisit/nenoform.hh,
src/ltlvisit/postfix.cc, src/ltlvisit/postfix.hh,
src/ltlvisit/randomltl.cc, src/ltlvisit/randomltl.hh,
src/ltlvisit/reduce.cc, src/ltlvisit/reduce.hh,
src/ltlvisit/simpfg.cc, src/ltlvisit/simpfg.hh,
src/ltlvisit/simplify.cc, src/ltlvisit/simplify.hh,
src/ltlvisit/snf.cc, src/ltlvisit/snf.hh, src/ltlvisit/tostring.cc,
src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh,
src/ltlvisit/wmunabbrev.cc, src/ltlvisit/wmunabbrev.hh,
src/neverparse/neverclaimparse.yy, src/sabatest/sabacomplementtgba.cc,
src/tgba/bdddict.cc, src/tgba/formula2bdd.cc, src/tgba/taatgba.cc,
src/tgba/taatgba.hh, src/tgbaalgos/eltl2tgba_lacim.cc,
src/tgbaalgos/ltl2taa.cc, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_lacim.cc, src/tgbaalgos/minimize.cc,
src/tgbaalgos/randomgraph.cc, src/tgbaparse/tgbaparse.yy,
src/tgbatest/complementation.cc, src/tgbatest/ltl2tgba.cc,
src/tgbatest/ltlprod.cc, src/tgbatest/mixprod.cc,
src/tgbatest/randtgba.cc: Massive adjustment!
* src/tgbatest/reductgba.cc: Delete.
bf62d439c9