Remove lib-src/b2m.c and b2m.pl.

Remove lib-src/b2m.c and b2m.pl.
Emacs does not use Babyl files since 23.1, and you can use M-x unrmail.

* msdos/mainmake.v2 (install): Remove b2m.

* lisp/emacs-lisp/authors.el (authors-valid-file-names): Add b2m.c.

* lib-src/b2m.c, lib-src/b2m.pl: Remove files.
* lib-src/Makefile.in (INSTALLABLES): Remove b2m.
* lib-src/makefile.w32-in ($(BLD)/b2m.$(O)): Remove.

* doc/emacs/ack.texi (Acknowledgments): No more b2m.c.

* admin/quick-install-emacs (PUBLIC_LIBSRC_BINARIES): Remove b2m.

* INSTALL, make-dist: Remove references to b2m.
* Makefile.in (MAN_PAGES): Remove b2m.1.