Adding att_xfer example to default dialplan

conf/dialplan/default.xml

@@ -250,6 +250,7 @@
 	<action application="bind_meta_app" data="1 b s execute_extension::dx XML features"/>
 	<action application="bind_meta_app" data="2 b s record_session::$${recordings_dir}/${caller_id_number}.${strftime(%Y-%m-%d-%H-%M-%S)}.wav"/>
 	<action application="bind_meta_app" data="3 b s execute_extension::cf XML features"/>
+	<action application="bind_meta_app" data="4 b s execute_extension::att_xfer XML features"/>
 	<action application="set" data="ringback=${us-ring}"/>
 	<action application="set" data="transfer_ringback=$${hold_music}"/>
 	<action application="set" data="call_timeout=30"/>