Remove our in tree gettext version and replace with a mechanism to import it.

Remove our in tree gettext version and replace with a mechanism to import it.

	* autogen.sh: use autopoint to poulate the gettext code; simplify.

	* po/Rules-lyx: move the LyX-specific code of the Makefile here.

	* configure.ac: add magic incantation telling autopoint to import
	gettext 0.16.1. Generate config.h in toplevel directory to please
	gettext.

	* src/tex2lyx/Makefile.am:
	* src/client/Messages.cpp: compile fix

	* remove all files that came from a gettext distribution.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@25167 a592a061-630c-0410-9148-cb99ea01b6c8