output/shout: add possibility to set url

Added a new optional parameter for the shout plugin called "url".

doc/mpd.conf.5

@@ -464,6 +464,9 @@ connect to the icecast server.  The default is 2 seconds.
 .B description <description>
 This specifies a description of the stream.
 .TP
+.B url <url>
+This specifies a URL associated with the stream.
+.TP
 .B genre <genre>
 This specifies the genre(s) of the stream.
 .SH FILES

doc/mpdconf.example

@@ -235,6 +235,7 @@ input {
 ##	protocol	"icecast2"		# optional
 ##	user		"source"		# optional
 ##	description	"My Stream Description"	# optional
+##	url		"http://example.com"	# optional
 ##	genre		"jazz"			# optional
 ##	public		"no"			# optional
 ##	timeout		"2"			# optional

doc/user.xml

@@ -1557,6 +1557,15 @@ cd mpd-version</programlisting>
                   Sets a short description of the stream (optional).
                 </entry>
               </row>
+              <row>
+                <entry>
+                  <varname>url</varname>
+                  <parameter>URL</parameter>
+                </entry>
+                <entry>
+                  Sets a URL associated with the stream (optional).
+                </entry>
+              </row>
               <row>
                 <entry>
                   <varname>public</varname>