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/doc/examples/osmo-msc/osmo-msc.cfg b/doc/examples/osmo-msc/osmo-msc.cfg
new file mode 100644
index 0000000..6cb9e4e
--- /dev/null
+++ b/doc/examples/osmo-msc/osmo-msc.cfg
@@ -0,0 +1,19 @@
+!
+! OsmoMSC configuration saved from vty
+!
+line vty
+ no login
+!
+network
+ network country code 1
+ mobile network code 1
+ short name OsmoMSC
+ long name OsmoMSC
+ auth policy closed
+ location updating reject cause 13
+ encryption a5 0
+ rrlp mode none
+ mm info 1
+msc
+ mgcpgw remote-ip 192.168.0.132
+ assign-tmsi