- Reorganized ITTI messages definition by groups (MAC, PDCP and RRC).
- Added support for some NAS / S1AP messages.

S1AP:
- Corrected MME selection in handle NAS first request.
- Modified some messages definition.

git-svn-id: http://svn.eurecom.fr/openair4G/trunk@4429 818b1a75-f10b-46b9-bf7c-635c3b92a50f