add cepstral legal goodies

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@1912 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/asr_tts/mod_cepstral/mod_cepstral.c

@@ -27,6 +27,9 @@
  *
  *
  * mod_cepstral.c -- Cepstral Interface
+ * 
+ * Some material based on the Cepstral Swift SDK, 
+ * Copyiright Cepstral LLC and used by permission
  *
  */
 #ifdef __ICC