Feature/what is network number handling (#304)

* Add What-Is-Network-Number handling.

Add What-Is-Network-Number and Network-Number-Is network layer handling.
Refactor npdu_encode_npdu_network() from router specific code.
Add unit test for NDPU network message
Add app for What-Is-Network-Number
Add app for Network-Number-Is
Add send helper for What-Is-Network-Number
Add send helper for Network-Number-Is

* added sys/debug.c to ports builds for use of debug_printf() in npdu handler.

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>

ports/atmega168/Makefile

@@ -51,6 +51,7 @@ CSRC = main.c \
 BASICSRC = $(BACNET_BASIC)/tsm/tsm.c \
 	$(BACNET_BASIC)/npdu/h_npdu.c \
 	$(BACNET_BASIC)/sys/bigend.c \
+	$(BACNET_BASIC)/sys/debug.c \
 	$(BACNET_BASIC)/service/s_iam.c \
 	$(BACNET_BASIC)/service/h_noserv.c
 

ports/atmega168/bacnet.cproj

@@ -156,6 +156,10 @@
       <SubType>compile</SubType>
       <Link>BACnet Handlers\bigend.c</Link>
     </Compile>
+    <Compile Include="..\..\src\bacnet\basic\sys\debug.c">
+      <SubType>compile</SubType>
+      <Link>BACnet Handlers\debug.c</Link>
+    </Compile>
     <Compile Include="..\..\src\bacnet\basic\npdu\h_npdu.c">
       <SubType>compile</SubType>
       <Link>BACnet Handlers\h_npdu.c</Link>

ports/atmega168/bacnet.ewp

@@ -3191,6 +3191,9 @@
         <file>
             <name>$PROJ_DIR$\..\..\src\bacnet\basic\sys\bigend.c</name>
         </file>
+        <file>
+            <name>$PROJ_DIR$\..\..\src\bacnet\basic\sys\debug.c</name>
+        </file>
         <file>
             <name>$PROJ_DIR$\..\..\src\bacnet\datalink\crc.c</name>
         </file>