Adding reference to ices home page. Anyone that has tested with ices2 ?

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@58224 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_ices.c

@@ -22,6 +22,8 @@
  *
  * \author Mark Spencer <markster@digium.com>
  * 
+ * \extref ICES - http://www.icecast.org/ices.php
+ *
  * \ingroup applications
  */