Added externs declarations to header files to handle C++ compilation.

Cleaned up BACnet/IP API a little.

bacnet-stack/awf.h

@@ -62,8 +62,11 @@ typedef struct BACnet_Atomic_Write_File_Data
   unsigned fileDataLength;
 } BACNET_ATOMIC_WRITE_FILE_DATA;
 
-// Atomic Write File
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
 
+// Atomic Write File
 // encode service
 int awf_encode_apdu(
   uint8_t *apdu, 
@@ -108,5 +111,9 @@ void test_AtomicWriteFile(Test * pTest);
 void test_AtomicWriteFileAck(Test * pTest);
 #endif
 
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
 #endif