doc: remove Preface.xml

This was never filled out, so might as well just delete it.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

doc/publican/Preface.xml

@@ -1,20 +0,0 @@
-<?xml version='1.0' encoding='utf-8' ?>
-<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
-"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
-<!ENTITY % BOOK_ENTITIES SYSTEM "Wayland.ent">
-%BOOK_ENTITIES;
-]>
-
-<preface>
-  <title>Acknowledgments</title>
-
-  <para>
-  TODO: Kristian has to fill up this with one or two paragraphs and a small
-  "thank you": http://en.wikipedia.org/wiki/Preface
-  </para>
-  <literallayout>
-Best,
-
-	Kristian Høgsberg
-  </literallayout>
-</preface>

doc/publican/Wayland.xml

@@ -6,7 +6,6 @@
 <book>
   <xi:include href="Book_Info.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
   <xi:include href="Foreword.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
-  <xi:include href="Preface.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
   <xi:include href="Introduction.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
   <xi:include href="Compositors.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />
   <xi:include href="Architecture.xml" xmlns:xi="http://www.w3.org/2001/XInclude" />

doc/publican/meson.build

@@ -12,7 +12,6 @@ foreach src : files([
 	'Book_Info.xml',
 	'Author_Group.xml',
 	'Foreword.xml',
-	'Preface.xml',
 	'Revision_History.xml',
 	'Protocol.xml',
 	'Xwayland.xml',