Add support the bounded star operator [*i..j].

* src/ltlast/bunop.hh, src/ltlast/bunop.cc: New files for
bounded unary operators.
* src/ltlast/Makefile.am, src/ltlast/allnodes.hh: Add them.
* src/ltlast/predecl.hh (bunop): Declare.
* src/ltlast/unop.hh, src/ltlast/unop.cc (Star): Remove
declaration of Star and associated code.
* src/ltlast/visitor.hh: Add visit(bunop* node) methods.
* src/ltlparse/ltlparse.yy, src/ltlparse/ltlscan.ll: Add parse
rules for LTL.  This required passing the parse_error list
to the lexer, so it can report scanning errors when it reads
a number that does not fit in an unsigned int.
* src/ltlparse/parsedecl.hh (YY_DECL): Take error_list
as third argument.
* src/ltltest/consterm.test, src/ltltest/tostring.test,
src/ltltest/equals.test, src/tgbatest/ltl2tgba.test: More tests.
* src/ltlvisit/basicreduce.cc, src/ltlvisit/clone.cc,
src/ltlvisit/clone.hh, src/ltlvisit/consterm.cc,
src/ltlvisit/dotty.cc, src/ltlvisit/mark.cc,
src/ltlvisit/nenoform.cc, src/ltlvisit/postfix.cc,
src/ltlvisit/postfix.hh, src/ltlvisit/reduce.cc,
src/ltlvisit/syntimpl.cc, src/ltlvisit/tostring.cc,
src/ltlvisit/tunabbrev.cc, src/tgba/formula2bdd.cc,
src/tgbaalgos/eltl2tgba_lacim.cc, src/tgbaalgos/ltl2taa.cc,
src/tgbaalgos/ltl2tgba_lacim.cc: Adjust syntax to use
"bunop::Star" instead of "unop::Star".
* src/tgbaalgos/ltl2tgba_fm.cc: Likewise, but also adjust
the code to handle the bounds of the operator.

src/ltltest/tostring.test

@@ -61,3 +61,9 @@ run 0 ../tostring '{a;b;{c && d*};**}|=>G{a*:b*}'
 run 0 ../tostring 'GF!{{a || c} && b}'
 run 0 ../tostring 'GF!{{a || c*} && b}<>->{{!a}*}'
 run 0 ../tostring 'GF{{a || c*} & b[*]}[]->{d}'
+run 0 ../tostring '{a[*2..3]}'
+run 0 ../tostring '{a[*0..1]}'
+run 0 ../tostring '{a[*0..]}'
+run 0 ../tostring '{a[*..]}'
+run 0 ../tostring '{a[*1..]}'
+run 0 ../tostring '{a[*2..3][*4..5]}'