Add Doxygen web tag file to HTML book archive

This adds the Doxygen web tag file to the HTML book archive in addition
to the local tag file which was already included. Fixes issue #3.

Author: PeterFeicht

Makefile

@@ -125,9 +125,9 @@ release: all
 	# zip the html output
 	pushd "output"; \
 	tar c$(TAR_OPTION)f "../release/html-book-$(VERSION).tar.$(TAR_FORMAT)" "reference" \
-		"cppreference-doxygen-local.tag.xml" ; \
+		"cppreference-doxygen-local.tag.xml" "cppreference-doxygen-web.tag.xml" ; \
 	zip -qr "../release/html-book-$(VERSION).zip" "reference" \
-		"cppreference-doxygen-local.tag.xml" ; \
+		"cppreference-doxygen-local.tag.xml" "cppreference-doxygen-web.tag.xml" ; \
 	popd
 
 	# zip qch