Implement IuCS (large refactoring and addition)

osmo-nitb becomes osmo-msc
add DIUCS debug log constant
add iucs.[hc]
add msc vty, remove nitb vty
add libiudummy, to avoid linking Iu deps in tests
Use new msc_tx_dtap() instead of gsm0808_submit_dtap()
libmgcp: add mgcpgw client API
bridge calls via mgcpgw

Enable MSC specific CTRL commands, bsc_base_ctrl_cmds_install() still needs to
be split up.

Change-Id: I5b5b6a9678b458affa86800afb1ec726e66eed88
diff --git a/include/openbsc/vlr.h b/include/openbsc/vlr.h
index 09e2ff4..619971a 100644
--- a/include/openbsc/vlr.h
+++ b/include/openbsc/vlr.h
@@ -156,7 +156,10 @@
 	struct {
 		/* pending requests */
 		bool is_paging;
+		/* list of struct subscr_request */
 		struct llist_head requests;
+		uint8_t lac;
+		enum ran_type attached_via_ran;
 	} cs;
 };
 
@@ -190,6 +193,10 @@
 	int (*set_ciph_mode)(void *msc_conn_ref, enum vlr_ciph ciph_mode,
 			     bool retrieve_imeisv);
 
+	/* UTRAN: send Common Id (when auth+ciph are complete) */
+	int (*tx_common_id)(void *msc_conn_ref);
+
+
 	/* notify MSC/SGSN that the subscriber data in VLR has been updated */
 	void (*subscr_update)(struct vlr_subscr *vsub);
 	/* notify MSC/SGSN that the given subscriber has been associated