m2ua: Create a MTP Link class using SCTP/M2UA for the transport

This is a MTP Link that can be used with a MTP LinkSet. E.g. with
some config changes one could use cellmgr_ng or udt_relay over a
M2UA link.
diff --git a/include/Makefile.am b/include/Makefile.am
index a0a54b9..6771b84 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -1,5 +1,5 @@
 noinst_HEADERS = mtp_level3.h mtp_data.h ipaccess.h thread.h mtp_pcap.h \
 		 mgcp_ss7.h bss_patch.h bssap_sccp.h bsc_data.h udp_input.h \
-                 snmp_mtp.h cellmgr_debug.h bsc_sccp.h bsc_ussd.h
+                 snmp_mtp.h cellmgr_debug.h bsc_sccp.h bsc_ussd.h sctp_m2ua.h
 
 SUBDIRS = mgcp