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/src/osmo-bsc/osmo_bsc_api.c b/src/osmo-bsc/osmo_bsc_api.c
index bac5e47..8c33e2b 100644
--- a/src/osmo-bsc/osmo_bsc_api.c
+++ b/src/osmo-bsc/osmo_bsc_api.c
@@ -536,7 +536,7 @@
 	.sapi_n_reject = bsc_sapi_n_reject,
 	.cipher_mode_compl = bsc_cipher_mode_compl,
 	.compl_l3 = bsc_compl_l3,
-	.dtap  = bsc_dtap,
+	.dtap = bsc_dtap,
 	.assign_compl = bsc_assign_compl,
 	.assign_fail = bsc_assign_fail,
 	.clear_request = bsc_clear_request,