Feature/apdu null length returned (#285)

* Add APDU as NULL to get BACnet type lengths.

* Fix bacapp copy test to succeed

* fix BACnet REAL and DOUBLE decode

* Add unit test for NULL APDU encoding for length

* Add unit tests for bacapp context

* refactor host-n-port to hostnport.c module

* fix BVLC decoder

* additional unit testing for bacapp

* include bacdevobjpropref module in builds

* simplify bacapp snprintf to be able to return length

* adjust compiler for variable-length arrays

* fix bug found by scan-build

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

src/bacnet/basic/object/device.c

@@ -210,7 +210,7 @@ static object_functions_t My_Object_Table[] = {
         Trend_Log_Write_Property, Trend_Log_Property_Lists, TrendLogGetRRInfo,
         NULL /* Iterator */, NULL /* Value_Lists */, NULL /* COV */,
         NULL /* COV Clear */, NULL /* Intrinsic Reporting */ },
-#if (BACNET_PROTOCOL_REVISION >= 14) && defined(BACAPP_LIGHTING_COMMAND)
+#if (BACNET_PROTOCOL_REVISION >= 14)
     { OBJECT_LIGHTING_OUTPUT, Lighting_Output_Init, Lighting_Output_Count,
         Lighting_Output_Index_To_Instance, Lighting_Output_Valid_Instance,
         Lighting_Output_Object_Name, Lighting_Output_Read_Property,