* taf-kit/src/parser_options.hxx: Remove the default ' ' character
	from the list of spaces when specified via --parser="SPACE=...
	* taf-kit/tests/vcsn-char-b.test: Fix loop.

	* taf-kit/tests/vcsn-char-b.test: Here.

	* ChangeLog: Write what should have gone in r2182.

Any character can be escaped.
Any special character that is escaped is seen as a basic letter.
Everything is based on a simple "escape" function.
It is currently not possible to have *(lex_escape_ch_p)[&fun]
return an escaped sequence, it only works on a single char.
- Solve ticket #171.
- This fix does not enable the support of escaped characters in the
rational expression parser.
	* taf-kit/src/parser_options.hxx: Add escape function.
	* taf-kit/src/parser_options.hh: Add escape function.
	* taf-kit/tests/vcsn-char-b.test: Add a test on the ascii alphabet.

	* src/tests/include/Makefile.am: transition_coherence_test.hh
	  was incorrectly spelt; fix spelling.

	Don't export CPPFLAGS or LDFLAGS, as this breaks configure -C.
	This bug was previously corrected in the old vcsn-boost.m4,
	which was just a copy of an older ax_boost_base.m4, in r1788.
	This time I've reported it upstream in an attempt to make sure this
	problem doesn't arise again.
	* build-aux/ax_boost_base.m4
	* build-aux/ax_boost_wserialization.m4

	* Makefile.am: Add missing file to noinst_HEADERS.

	* build-aux/Makefile.am: Add new boost .m4 files.
	* build-aux/ax_boost_base.m4: New. This replaces vcsn-boost.m4 with
	  a more up-to-date version of the same file, with its upstream name.
	* build-aux/ax_boost_wserialization.m4: New. Used to detect the
	  BOOST serialization library.
	* build-aux/vcsn-boost.m4: Remove. See above.
	* configure.ac: Detect the serialization library explicitly. Add a
	  comment saying that we need to do the same thing for the graph
	  library, but there's currently no macro for that. I've asked
	  upstream for help.

	* ChangeLog: Fix my previous entries.

	To enable the use of standalone rational expressions described in xml
	files, add the OUTPUT_TYPE_EXP and INPUT_TYPE_EXP possibilities.
	Split output_type in output_aut_type and output_exp_type to have
	different default output for automata (xml) and rational expressions
	(exp).
	* taf-kit/src/common.hh: split output_type.
	* taf-kit/src/main.cc: split output_type.
	* taf-kit/src/pipe.hh: Add *_TYPE_EXP.
	* taf-kit/src/pipe.hxx: split output_type.
	* taf-kit/src/pipe_writers.hh: split output_type.
	* taf-kit/src/pipe_writers.hxx: split output_type. Prepare to support
	xml standalone rational expressions' files. Improve the error
	messages.

non-portable.

	* transition_coherence_test.hh: here.

	* bmig/bmig_support.hh: here.

	* include/vaucanson/algorithms/rw_composition.hxx (rw_composition):
	  res -> ret.