sms: Introduce a SMS queue that will be responsible for delivery

The SMSqueue will be responsible of sending to the user. It will
do so in a loop and will also try not to overload the BTS. This
means the throughput of SMS will be limited.
diff --git a/openbsc/src/Makefile.am b/openbsc/src/Makefile.am
index 2766d93..4f3bf9e 100644
--- a/openbsc/src/Makefile.am
+++ b/openbsc/src/Makefile.am
@@ -35,7 +35,7 @@
 
 libmgcp_a_SOURCES = mgcp/mgcp_protocol.c mgcp/mgcp_network.c mgcp/mgcp_vty.c
 
-bsc_hack_SOURCES = bsc_hack.c bsc_init.c bsc_vty.c vty_interface_layer3.c
+bsc_hack_SOURCES = bsc_hack.c bsc_init.c bsc_vty.c vty_interface_layer3.c sms_queue.c
 bsc_hack_LDADD = libmsc.a libbsc.a libvty.a libmsc.a \
 		-ldl -ldbi $(LIBCRYPT) $(LIBOSMOVTY_LIBS)