Bring back our own XML catalogs

Avoid 429 errors from W3C
diff --git a/lib/dtds/xhtml/html2dita/preprocess.xsl b/lib/dtds/xhtml/html2dita/preprocess.xsl
new file mode 100644
index 0000000..c935542
--- /dev/null
+++ b/lib/dtds/xhtml/html2dita/preprocess.xsl
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8" ?>

+<!-- This file is part of the DITA Open Toolkit project hosted on 

+    Sourceforge.net. See the accompanying license.txt file for 

+    applicable licenses.-->

+<!-- (c) Copyright IBM Corp. 2006 All Rights Reserved. -->

+

+<xsl:stylesheet version="1.0"

+                xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

+

+<xsl:output method="xml" />

+

+<xsl:template match="*" priority="10">

+    <xsl:element name="{local-name()}">

+        <xsl:for-each select="@*">

+            <xsl:attribute name="{local-name()}">

+                <xsl:value-of select="." />

+            </xsl:attribute>

+        </xsl:for-each>

+        <xsl:apply-templates />

+    </xsl:element>

+</xsl:template>

+

+<xsl:template match="comment()">

+    <xsl:comment><xsl:value-of select="."/></xsl:comment>

+</xsl:template>

+

+<xsl:template match="*|processing-instruction()|text()">

+    <xsl:copy>

+        <xsl:apply-templates select="*|processing-instruction()|text()"/>

+    </xsl:copy>

+</xsl:template>

+

+</xsl:stylesheet>