Feature/bacnet discover dnet devices (#583)

* Added an example application to discover devices and their objects and properties on a specific destination network. The application uses a BACnet Discovery FSM module along with the BACnet R/W FSM.  The BACnet Discovery module stores the binary property data in Keylists and includes device object property queries and iterators.

* Added callback from BACnet R/W FSM module for I-Am messages.

* Removed dependency in BACnet R/W FSM module on rpm_ack_decode_service_request() which uses calloc/free value lists.  Created an alternate RPM-ACK to RP-ACK processing function.

* Changed RPM handler to skip over unknown property values

apps/server-discover/Makefile

@@ -0,0 +1,45 @@
+#Makefile to build BACnet Application using GCC compiler
+
+# Executable file name - BACnet Server-Discover Application
+TARGET = bacdiscover
+# BACnet objects that are used with this app
+# BACnet objects that are used with this app
+BACNET_OBJECT_DIR = $(BACNET_SRC_DIR)/bacnet/basic/object
+BACNET_CLIENT_DIR = $(BACNET_SRC_DIR)/bacnet/basic/client
+
+SRC = main.c \
+	$(BACNET_OBJECT_DIR)/client/device-client.c \
+	$(BACNET_OBJECT_DIR)/netport.c \
+	$(BACNET_CLIENT_DIR)/bac-discover.c \
+	$(BACNET_CLIENT_DIR)/bac-rw.c
+
+# TARGET_EXT is defined in apps/Makefile as .exe or nothing
+TARGET_BIN = ${TARGET}$(TARGET_EXT)
+
+OBJS += ${SRC:.c=.o}
+
+all: ${BACNET_LIB_TARGET} Makefile ${TARGET_BIN}
+
+${TARGET_BIN}: ${OBJS} Makefile ${BACNET_LIB_TARGET}
+	${CC} ${PFLAGS} ${OBJS} ${LFLAGS} -o $@
+	size $@
+	cp $@ ../../bin
+
+${BACNET_LIB_TARGET}:
+	( cd ${BACNET_LIB_DIR} ; $(MAKE) clean ; $(MAKE) -s )
+
+.c.o:
+	${CC} -c ${CFLAGS} $*.c -o $@
+
+.PHONY: depend
+depend:
+	rm -f .depend
+	${CC} -MM ${CFLAGS} *.c >> .depend
+
+.PHONY: clean
+clean:
+	rm -f core ${TARGET_BIN} ${OBJS} $(TARGET).map ${BACNET_LIB_TARGET}
+
+.PHONY: include
+include: .depend
+