* po/update_potfiles_in.sh: now simply calls the recent intltools
	features; they work better than hand-crafted half-ignorant
	scripts. Thanks to Kenneth Rohde Christiansen <kenneth@gnu.org>
	for the tip.

	* po/POTFILES.in: added back two files update_potfiles_in.sh
	didn't take into account. Now this file is not automatically
	generated anymore!
	* po/POTFILES.skip: told 	ntltool-update -m what files to ignore
	(the usual suspects, in fact).