doc/user.xml: rewrite the "Introduction" section with text from the website

doc/user.xml

@@ -9,32 +9,16 @@
     <title>Introduction</title>
 
     <para>
-      This document is work in progress.  Most of it may be incomplete
-      yet.  Please help!
+      <application>Music Player Daemon</application>
+      (<application>MPD</application>) is a flexible, powerful,
+      server-side application for playing music.  Through plugins and
+      libraries it can play a variety of sound files while being
+      controlled by its network protocol.
     </para>
 
     <para>
-      <application>MPD</application> (Music Player Daemon) is, as the
-      name suggests, a server software allowing you to remotely play
-      your music, handle playlists, deliver music (HTTP streams with
-      various sub-protocols) and organize playlists.
-    </para>
-
-    <para>
-      It has been written with minimal resource usage and stability in
-      mind!  Infact, it runs fine on a Pentium 75, allowing you to use
-      your cheap old PC to create a stereo system!
-    </para>
-
-    <para>
-      <application>MPD</application> supports also gapless playback,
-      buffered audio output, and crossfading!
-    </para>
-
-    <para>
-      The separate client and server design allows users to choose a
-      user interface that best suites their tastes independently of
-      the underlying daemon, which actually plays music!
+      This document is work in progress.  Most of it may be incomplete
+      yet.  Please help!
     </para>
   </chapter>