Replaced ITTI_ERROR by DevAssert or DevCheck, error in ITTI are critical and should stop the program!
Disabled debug log in ITTI by default.
Added ITTI_MSG_NAME and ITTI_MSG_INSTANCE defines to simplify acces to some part of message header.

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4284 818b1a75-f10b-46b9-bf7c-635c3b92a50f