Fix last documentation installation problem.
Fix last documentation installation problem.

Regular reference manuals are not installed on the web anymore (only the
web-specific version).

2016-04-23  Didier Verna  <didier@didierverna.net>

	* doc/Makefile (MAN):
	(REF):
	(FILES):
	(PDF_MAN):
	(PDF_REF):
	(HTML_MAN):
	(HTML_REF): New variables.
	(install-at): Only deal with the user manual(s), not the reference
	ones any more.
	(install):
	(install-www): Update accordingly.

didierverna/focus,didierverna/focus