Resolving KW issue with SoftwareSerial destructor

Signed-off-by: Brian Baltz <brian.a.baltz@intel.com>

Author: Brian Baltz

libraries/SoftwareSerial/SoftwareSerial.h

@@ -73,7 +73,7 @@ class SoftwareSerial : public Stream
 public:
   // public methods
   SoftwareSerial(uint32_t receivePin, uint32_t transmitPin, bool inverse_logic = false);
-  ~SoftwareSerial();
+  virtual ~SoftwareSerial();
   void begin(long speed);
   bool listen();
   void end();