Merge remote-tracking branch 'origin/x2' into develop_integration_2018_w36

cmake_targets/CMakeLists.txt

common/utils/LOG/log.c

openair2/COMMON/sctp_messages_def.h

openair2/COMMON/sctp_messages_types.h

openair2/COMMON/x2ap_messages_def.h

openair2/ENB_APP/enb_app.c

openair2/X2AP/x2ap_common.h

openair2/X2AP/x2ap_eNB.c

openair2/X2AP/x2ap_eNB.h

openair2/X2AP/x2ap_eNB_defs.h

openair2/X2AP/x2ap_eNB_handler.c

openair2/X2AP/x2ap_eNB_handler.h

openair2/X2AP/x2ap_eNB_management_procedures.c

openair2/X2AP/x2ap_eNB_management_procedures.h

openair3/SCTP/sctp_common.c

openair3/SCTP/sctp_eNB_itti_messaging.c

openair3/SCTP/sctp_eNB_itti_messaging.h

openair3/SCTP/sctp_eNB_task.c

targets/COMMON/create_tasks.c