lwg-active.html: Remove.

	* doc/html/ext/lwg-active.html: Remove.
	* doc/html/ext/lwg-closed.html: Ditto.
	* doc/html/ext/lwg-defects.html: Ditto.

	* doc/Makefile.am (xml_extradir): Remove.
	(xml_extra): Ditto.
	(stamp-html-docbook-lwg): Remove recipe...
	(stamp-html-docbook-data): ...and its use here.
	* doc/Makefile.in: Regenerate.

	* doc/xml/manual/intro.xml: Shorten two paragraphs explaining
	the relationship to the upstream working group.
	Replace a local link to ../ext/lwg-active.html by the upstream one.
	Replace all reference to ../ext/lwg-defects.html by a new entity
	&DR; which refers to the upstream address.

From-SVN: r245258