www cleanup mega commit:

- Move includes.nav*.sgml to share/sgml/navibar.ent and
   <lang>/share/sgml/nabibar.l10n.ent.

 - Move includes.sgml and includes.xsl to
   share/sgml/common.ent, share/sgml/header.ent, <lang>/share/sgml/l10n.ent,
   and <lang>?share/sgml/header.l10n.ent.

 - Move most of XSLT libraries to share/sgml/*.xsl and
   <lang>/share/sgml/*.xsl.

 - Move news.xml and other *.xml files for the similar purpose
   to share/sgml/*.xml and <lang>/share/sgml/*.xml.

 - Switch to use a custom DTD for HTML document.  Now we use
   "-//FreeBSD//DTD HTML 4.01 Transitional-Based Extension", which is
   HTML 4.01 + some entities previously pulled via
   "<!ENTITY % includes SYSTEM "includes.sgml"> %includes;" line.
   The location of entity file will be resolved by using catalog file.

 - Add DOCTYPE declearation to XML documents.  This makes the followings
   possible:

   * Use of &foo; entities for SGML in an XML file instead of defining
     {$foo} as the same content.

   * &symbolic; entities for Latin characters.

 - Duplicated information between SGML and XML, or English and
   translated doc, has been removed as much as possible.

en/share/sgml/catalog

@@ -0,0 +1,12 @@
+--
+ $FreeBSD$
+--
+
+PUBLIC "-//FreeBSD//ENTITIES FreeBSD L10N Entities//EN"
+       "l10n.ent"
+
+PUBLIC "-//FreeBSD//ENTITIES HTML FreeBSD Header L10N Entities//EN"
+       "header.l10n.ent"
+
+PUBLIC "-//FreeBSD//ENTITIES HTML FreeBSD Navigation Bar L10N Entities//EN"
+       "navibar.l10n.ent"

en/share/sgml/catalog.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<!DOCTYPE catalog PUBLIC "-//OASIS//DTD Entity Resolution XML Catalog V1.0//EN"
+        "http://www.oasis-open.org/committees/entity/release/1.0/catalog.dtd">
+
+<!-- $FreeBSD$ -->
+
+<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog">
+  <rewriteSystem systemIdStartString="http://www.FreeBSD.org/XML/www/lang/"
+                 rewritePrefix="../../"/>
+  <rewriteURI uriStartString="http://www.FreeBSD.org/XML/www/lang/"
+              rewritePrefix="../../"/>
+</catalog>

en/share/sgml/header.l10n.ent

@@ -0,0 +1,4 @@
+<!-- $FreeBSD$ -->
+
+<!-- FreeBSD HTML Header L10N Entities -->
+<!-- PUBLIC "-//FreeBSD//ENTITIES HTML FreeBSD Header L10N Entities//EN" -->

en/share/sgml/l10n.ent

@@ -0,0 +1,9 @@
+<!-- $FreeBSD$ -->
+
+<!-- FreeBSD L10N Entities -->
+<!-- PUBLIC "-//FreeBSD//ENTITIES FreeBSD L10N Entities//EN" -->
+
+<!ENTITY % url.enbase.eq.base "INCLUDE">
+
+<!ENTITY url.doc.langcode    'en_US.ISO8859-1'>
+<!ENTITY xml.encoding        'iso-8859-1'>

en/share/sgml/libcommon.xsl

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="ISO-8859-1" ?>
+<!DOCTYPE xsl:stylesheet PUBLIC "-//FreeBSD//DTD FreeBSD XSLT 1.0 DTD//EN"
+				"http://www.FreeBSD.org/XML/www/share/sgml/xslt10-freebsd.dtd">
+<!-- $FreeBSD$ -->
+
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
+  <xsl:import href="http://www.FreeBSD.org/XML/www/share/sgml/libcommon.xsl"/>
+
+</xsl:stylesheet>

en/share/sgml/navibar.l10n.ent

@@ -0,0 +1 @@
+<!-- $FreeBSD$ -->