stp: Begin to implement a signalling transfer point

This is creating a new application that will be a signalling
transfer point. Right now it is a stripped down version of
the udt_relay, which is a stripped down version of cellmgr_ng.
diff --git a/src/Makefile.am b/src/Makefile.am
index 0331406..dbed8fa 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -2,7 +2,7 @@
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOSCCP_CFLAGS) $(LIBOSMOVTY_CFLAGS) \
 		$(NEXUSWARE_C7_CFLAGS) $(NEXUSWARE_UNIPORTE_CFLAGS) $(UNIPORTE)
 
-sbin_PROGRAMS = cellmgr_ng udt_relay mgcp_mgw
+sbin_PROGRAMS = cellmgr_ng udt_relay osmo_stp mgcp_mgw
 
 mgcp_mgw_SOURCES = mgcp_ss7.c thread.c debug.c \
 		   mgcp/mgcp_protocol.c mgcp/mgcp_network.c mgcp/mgcp_vty.c
@@ -20,3 +20,8 @@
 		     bss_patch.c isup.c links.c sctp_m2ua.c
 udt_relay_LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOSCCP_LIBS) $(LIBOSMOVTY_LIBS) $(NEXUSWARE_C7_LIBS) \
 		   -lpthread -lnetsnmp -lcrypto -lm2ua -lsctp
+
+osmo_stp_SOURCES = main_stp.c mtp_layer3.c thread.c pcap.c link_udp.c snmp_mtp.c \
+		   debug.c vty_interface.c links.c isup.c
+osmo_stp_LDADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOSCCP_LIBS) $(LIBOSMOVTY_LIBS) $(NEXUSWARE_C7_LIBS) \
+		   -lpthread -lnetsnmp -lcrypto -lm2ua -lsctp