src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlparse/fmterror.cc, src/ltlparse/public.hh,
src/ltlvisit/dotty.cc, src/ltlvisit/dotty.hh,
src/ltlvisit/dump.cc, src/ltlvisit/dump.hh,
src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh,
src/misc/escape.cc, src/misc/escape.hh, src/tgba/bdddict.cc,
src/tgba/bdddict.hh, src/tgba/bddprint.cc, src/tgba/bddprint.hh,
src/tgbaalgos/dotty.cc, src/tgbaalgos/dotty.hh,
src/tgbaalgos/lbtt.cc, src/tgbaalgos/lbtt.hh,
src/tgbaalgos/neverclaim.cc, src/tgbaalgos/neverclaim.hh,
src/tgbaalgos/save.cc, src/tgbaalgos/save.hh,
src/tgbaalgos/gtec/status.cc, src/tgbaalgos/gtec/status.hh,
src/tgbaparse/fmterror.cc, src/tgbaparse/public.hh: Include <iosfwd>
in headers, and prefer <ostream> in the body whenever possible.
* src/sanity/style.test, HACKING: Check and document this.

(to_string_visitor::visitor(const atomic_prop*)): Use is_bare_word
to better check which atomic proposition need to be quoted.
* src/ltlparse/ltlscan.ll: Do not allow identifiers starting with F_
or G_.
* src/ltltest/equals.test, src/ltltest/tostring.test: More tests.

to_string_visitor): Do not parenthesize the top-level formula.
* tgbatest/explicit.test, tgbatest/explpro2.test,
tgbatest/explpro3.test, tgbatest/explprod.test,
tgbatest/readsave.test, tgbatest/tgbaread.test,
tgbatest/tripprod.test: Adjust expected output.
* sanity/style.test: Fix regexes to catch an error seen in
tostring.cc.

(subformula): Recognize `ATOMIC_PROP OP_POST_POS' and
`ATOMIC_PROP OP_POST_NEG'.
* src/ltlparse/ltlscan.ll: Introduce the not_prop start condition,
to restrict the set of atomic propositions allowed in places
where they are not expected.  Make `true' and `false' case insensitive.
* src/ltltest/parse.test, src/ltltest/tostring.test: More cases.
* src/ltlvisit/tostring.cc (to_string_visitor): Quote atomic
propositions equal to "true" or "false".

* src/sanity/Makefile.am (check-local): Run it.
* src/ltlvisit/nenoform.cc, src/ltlvisit/tostring.cc,
src/tgba/bdddict.cc, src/tgba/bddprint.cc, src/tgba/tgba.cc,
src/tgba/tgbaproduct.cc, src/tgbaalgos/lbtt.cc,
src/tgbaalgos/magic.cc, src/tgbaalgos/powerset.cc,
src/tgbaalgos/reachiter.cc, src/tgbaalgos/gtec/ce.cc,
src/tgbaalgos/gtec/gtec.cc, src/tgbatest/ltl2tgba.cc: Fix style
issues reported by style.test.

Convert a formula into a string parsable by Spin.
* src/tgbaalgos/neverclaim.hh, src/tgbaalgos/neverclaim.cc: New files.
Print the never claim in Spin format of a degeneralized TGBA.
* src/tgbaalgos/Makefile.am: Add them.
* src/tgbatest/ltl2tgba.cc: Add the option -N which outputs the
never claim in Spin format of a degeneralized TGBA.
* src/tgbatest/ltl2neverclaim.test: New file.
* src/tgbatest/Makefile.am: Add it.

* src/ltltest/tostring.test: Test these.

(to_string_visitor::visit(const atomic_prop*)): Quote propositions
that start with F, G, or X.
* src/ltltest/tostring.test: Test quoted propositions.
* src/tgbaalgos/save.cc (save_bfs::process_state): Escape " and +	characters in formulae.
* src/tgbatest/readsave.test: Test for this.

* Makefile.am, configure.ac, doc/Makefile.am, iface/Makefile.am,
iface/gspn/Makefile.am, iface/gspn/common.cc,
iface/gspn/common.hh, iface/gspn/dottyeesrg.cc,
iface/gspn/dottygspn.cc, iface/gspn/eesrg.cc, iface/gspn/eesrg.hh,
iface/gspn/gspn.cc, iface/gspn/gspn.hh, iface/gspn/ltlgspn.cc,
src/Makefile.am, src/ltlast/Makefile.am, src/ltlast/allnodes.hh,
src/ltlast/atomic_prop.cc, src/ltlast/atomic_prop.hh,
src/ltlast/binop.cc, src/ltlast/binop.hh, src/ltlast/constant.cc,
src/ltlast/constant.hh, src/ltlast/formula.cc,
src/ltlast/formula.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/Makefile.am,
src/ltlenv/defaultenv.cc, src/ltlenv/defaultenv.hh,
src/ltlenv/environment.hh, src/ltlparse/Makefile.am,
src/ltlparse/fmterror.cc, src/ltlparse/ltlparse.yy,
src/ltlparse/ltlscan.ll, src/ltlparse/parsedecl.hh,
src/ltlparse/public.hh, src/ltltest/Makefile.am,
src/ltltest/defs.in, src/ltltest/equals.cc,
src/ltltest/equals.test, src/ltltest/lunabbrev.test,
src/ltltest/nenoform.test, src/ltltest/parse.test,
src/ltltest/parseerr.test, src/ltltest/readltl.cc,
src/ltltest/tostring.cc, src/ltltest/tostring.test,
src/ltltest/tunabbrev.test, src/ltltest/tunenoform.test,
src/ltlvisit/Makefile.am, src/ltlvisit/clone.cc,
src/ltlvisit/clone.hh, src/ltlvisit/destroy.cc,
src/ltlvisit/destroy.hh, src/ltlvisit/dotty.cc,
src/ltlvisit/dotty.hh, src/ltlvisit/dump.cc, src/ltlvisit/dump.hh,
src/ltlvisit/lunabbrev.cc, src/ltlvisit/lunabbrev.hh,
src/ltlvisit/nenoform.cc, src/ltlvisit/nenoform.hh,
src/ltlvisit/postfix.cc, src/ltlvisit/postfix.hh,
src/ltlvisit/tostring.cc, src/ltlvisit/tostring.hh,
src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh,
src/misc/Makefile.am, src/misc/bddalloc.cc, src/misc/bddalloc.hh,
src/misc/bddlt.hh, src/misc/hash.hh, src/misc/minato.cc,
src/misc/minato.hh, src/misc/version.cc, src/misc/version.hh,
src/tgba/Makefile.am, src/tgba/bdddict.cc, src/tgba/bdddict.hh,
src/tgba/bddprint.cc, src/tgba/bddprint.hh, src/tgba/public.hh,
src/tgba/state.hh, src/tgba/statebdd.cc, src/tgba/statebdd.hh,
src/tgba/succiter.hh, src/tgba/succiterconcrete.cc,
src/tgba/succiterconcrete.hh, src/tgba/tgba.cc, src/tgba/tgba.hh,
src/tgba/tgbabddconcrete.cc, src/tgba/tgbabddconcrete.hh,
src/tgba/tgbabddconcretefactory.cc,
src/tgba/tgbabddconcretefactory.hh,
src/tgba/tgbabddconcreteproduct.cc,
src/tgba/tgbabddconcreteproduct.hh, src/tgba/tgbabddcoredata.cc,
src/tgba/tgbabddcoredata.hh, src/tgba/tgbabddfactory.hh,
src/tgba/tgbaexplicit.cc, src/tgba/tgbaexplicit.hh,
src/tgba/tgbaproduct.cc, src/tgba/tgbaproduct.hh,
src/tgba/tgbatba.cc, src/tgba/tgbatba.hh,
src/tgbaalgos/Makefile.am, src/tgbaalgos/dotty.cc,
src/tgbaalgos/dotty.hh, src/tgbaalgos/dupexp.cc,
src/tgbaalgos/dupexp.hh, src/tgbaalgos/emptinesscheck.cc,
src/tgbaalgos/emptinesscheck.hh, src/tgbaalgos/lbtt.cc,
src/tgbaalgos/lbtt.hh, src/tgbaalgos/ltl2tgba_fm.cc,
src/tgbaalgos/ltl2tgba_fm.hh, src/tgbaalgos/ltl2tgba_lacim.cc,
src/tgbaalgos/ltl2tgba_lacim.hh, src/tgbaalgos/magic.cc,
src/tgbaalgos/magic.hh, src/tgbaalgos/reachiter.cc,
src/tgbaalgos/reachiter.hh, src/tgbaalgos/save.cc,
src/tgbaalgos/save.hh, src/tgbaparse/Makefile.am,
src/tgbaparse/fmterror.cc, src/tgbaparse/parsedecl.hh,
src/tgbaparse/public.hh, src/tgbaparse/tgbaparse.yy,
src/tgbaparse/tgbascan.ll, src/tgbatest/Makefile.am,
src/tgbatest/bddprod.test, src/tgbatest/defs.in,
src/tgbatest/dupexp.test, src/tgbatest/emptchk.test,
src/tgbatest/emptchke.test, src/tgbatest/explicit.test,
src/tgbatest/explpro2.test, src/tgbatest/explpro3.test,
src/tgbatest/explprod.test, src/tgbatest/ltl2tgba.test,
src/tgbatest/ltlprod.test, src/tgbatest/mixprod.test,
src/tgbatest/readsave.test, src/tgbatest/spotlbtt.test,
src/tgbatest/tgbaread.test, src/tgbatest/tripprod.test,
wrap/Makefile.am, wrap/python/Makefile.am, wrap/python/buddy.i,
wrap/python/spot.i, wrap/python/cgi/Makefile.am,
wrap/python/cgi/ltl2tgba.in, wrap/python/tests/Makefile.am,
wrap/python/tests/bddnqueen.py, wrap/python/tests/interdep.py,
wrap/python/tests/ltl2tgba.py, wrap/python/tests/ltl2tgba.test,
wrap/python/tests/ltlparse.py, wrap/python/tests/ltlsimple.py,
wrap/python/tests/run.in: Add Copyright license.

* src/ltlvisit/dump.cc (dump): Likewise.
* src/ltlvisit/dotty.hh (dotty): Likewise.
* src/ltlvisit/dotty.cc (dotty): Likewise.
* src/ltlvisit/tostring.hh (to_string): Likewise.
* src/ltlvisit/tostring.cc (to_string): Likewise.

not a formula&.  This is more homogeneous.
* src/ltlvisit/dump.cc (dump): Likewise.
* src/ltlvisit/dotty.hh (dotty): Likewise.
* src/ltlvisit/dotty.cc (dotty): Likewise.
* src/ltlvisit/tostring.hh (to_string): Likewise.
* src/ltlvisit/tostring.cc (to_string): Likewise.
* src/ltltest/readltl.cc, src/ltltest/equals.cc,
src/ltltest/tostring.cc: Adjust usage.

spot::ltl:: prefixes.
(to_string(formula)): New function.
* src/ltlvisit/tostring.hh (to_string(formula)): Likewise.
* src/ltltest/tostring.cc: Use this new to_string function to
simplify.

* src/ltltest/tostring.cc: New files.
* src/ltlvisit/tostring.hh: From ast to string New files.
* src/ltlvisit/tostring.cc: From ast to string New files.