Modernized user guide, API reference, and FAQ generation. Overall

effect is to move away from DocBook SGML and DJ Delorie's doctool and
toward pure DocBook XSL.  (There remains just one use of doctool, and
we have plans for replacing it, too.)  See ChangeLog for details.

winsup/doc/faq-using.xml

@@ -1,3 +1,10 @@
+<?xml version="1.0" encoding='UTF-8'?>
+<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
+		"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
+
+<qandadiv id="faq.using">
+<title>Using Cygwin</title>
+
 <!-- faq-problems.xml -->
 <qandaentry id="faq.using.missing-dlls">
 <question><para>Why can't my application locate cygncurses-8.dll?  or cygintl-3.dll?  or cygreadline6.dll?  or ...?</para></question>
@@ -1243,3 +1250,4 @@ such as virtual memory paging and file caching.</para>
   difficult to make <literal>fork()</literal> work reliably.</para>
 </answer>
 </qandaentry>
+</qandadiv>