Get rid of externals annoyances by getting argp from gnulib, the way
	it should be done. It may be useful to use gnulib for other things
	too; in particular, current gnulib has just introduced complexity
	metrics and coverage checks.

	N.B. Only developers who wish to change the gnulib setup need to
	install gnulib; all the necessary files for compilation are in
	Subversion.

	Care is required when deciding what files should be checked in and
	which ignored, as gnulib does not (yet) support Subversion. Git users
	will be happy, as they are automatically catered for. I used a simple
	technique: before updating the gnulib settings, I removed the gnulib
	and m4 directories, and then I added to Subversion all the files that
	gnulib created.

	Also, note that because we already use lib/ for the Vaucanson libraries,
	gnulib-tool needs to be invoked with --source-base=gnulib, which is
	where it stores its source files.
	* Makefile.am: .
	* build-aux/link-warning.h: New.
	* configure.ac: .
	* gnulib/Makefile.am: New.
	* gnulib/alloca.c: New.
	* gnulib/alloca.in.h: New.
	* gnulib/argp-ba.c: New.
	* gnulib/argp-eexst.c: New.
	* gnulib/argp-fmtstream.c: New.
	* gnulib/argp-fmtstream.h: New.
	* gnulib/argp-fs-xinl.c: New.
	* gnulib/argp-help.c: New.
	* gnulib/argp-namefrob.h: New.
	* gnulib/argp-parse.c: New.
	* gnulib/argp-pin.c: New.
	* gnulib/argp-pv.c: New.
	* gnulib/argp-pvh.c: New.
	* gnulib/argp-xinl.c: New.
	* gnulib/argp.h: New.
	* gnulib/asnprintf.c: New.
	* gnulib/basename.c: New.
	* gnulib/dirname.c: New.
	* gnulib/dirname.h: New.
	* gnulib/error.c: New.
	* gnulib/error.h: New.
	* gnulib/exitfail.c: New.
	* gnulib/exitfail.h: New.
	* gnulib/float+.h: New.
	* gnulib/float.in.h: New.
	* gnulib/getopt.c: New.
	* gnulib/getopt.in.h: New.
	* gnulib/getopt1.c: New.
	* gnulib/getopt_int.h: New.
	* gnulib/gettext.h: New.
	* gnulib/intprops.h: New.
	* gnulib/malloc.c: New.
	* gnulib/mempcpy.c: New.
	* gnulib/printf-args.c: New.
	* gnulib/printf-args.h: New.
	* gnulib/printf-parse.c: New.
	* gnulib/printf-parse.h: New.
	* gnulib/rawmemchr.c: New.
	* gnulib/rawmemchr.valgrind: New.
	* gnulib/size_max.h: New.
	* gnulib/sleep.c: New.
	* gnulib/stdbool.in.h: New.
	* gnulib/stdint.in.h: New.
	* gnulib/stdio.in.h: New.
	* gnulib/stdlib.in.h: New.
	* gnulib/strcasecmp.c: New.
	* gnulib/strchrnul.c: New.
	* gnulib/strchrnul.valgrind: New.
	* gnulib/strerror.c: New.
	* gnulib/string.in.h: New.
	* gnulib/strings.in.h: New.
	* gnulib/stripslash.c: New.
	* gnulib/strncasecmp.c: New.
	* gnulib/strndup.c: New.
	* gnulib/strnlen.c: New.
	* gnulib/sysexits.in.h: New.
	* gnulib/unistd.in.h: New.
	* gnulib/vasnprintf.c: New.
	* gnulib/vasnprintf.h: New.
	* gnulib/vsnprintf.c: New.
	* gnulib/wchar.in.h: New.
	* gnulib/xalloc-die.c: New.
	* gnulib/xalloc.h: New.
	* gnulib/xmalloc.c: New.
	* gnulib/xsize.h: New.
	* gnulib/xstrndup.c: New.
	* gnulib/xstrndup.h: New.
	* gnulib: New.
	* m4/alloca.m4: New.
	* m4/argp.m4: New.
	* m4/dirname.m4: New.
	* m4/dos.m4: New.
	* m4/double-slash-root.m4: New.
	* m4/eoverflow.m4: New.
	* m4/error.m4: New.
	* m4/exitfail.m4: New.
	* m4/extensions.m4: New.
	* m4/float_h.m4: New.
	* m4/getopt.m4: New.
	* m4/gnulib-cache.m4: New.
	* m4/gnulib-common.m4: New.
	* m4/gnulib-comp.m4: New.
	* m4/gnulib-tool.m4: New.
	* m4/include_next.m4: New.
	* m4/inline.m4: New.
	* m4/intmax_t.m4: New.
	* m4/inttypes_h.m4: New.
	* m4/longlong.m4: New.
	* m4/malloc.m4: New.
	* m4/mempcpy.m4: New.
	* m4/printf.m4: New.
	* m4/rawmemchr.m4: New.
	* m4/size_max.m4: New.
	* m4/sleep.m4: New.
	* m4/stdbool.m4: New.
	* m4/stdint.m4: New.
	* m4/stdint_h.m4: New.
	* m4/stdio_h.m4: New.
	* m4/stdlib_h.m4: New.
	* m4/strcase.m4: New.
	* m4/strchrnul.m4: New.
	* m4/strerror.m4: New.
	* m4/string_h.m4: New.
	* m4/strings_h.m4: New.
	* m4/strndup.m4: New.
	* m4/strnlen.m4: New.
	* m4/sysexits.m4: New.
	* m4/unistd_h.m4: New.
	* m4/vasnprintf.m4: New.
	* m4/vsnprintf.m4: New.
	* m4/wchar.m4: New.
	* m4/wchar_t.m4: New.
	* m4/wint_t.m4: New.
	* m4/xalloc.m4: New.
	* m4/xsize.m4: New.
	* m4/xstrndup.m4: New.
	* m4: New.
	* taf-kit/src/Makefile.am: .
	* taf-kit/src/main.cc: .