Fix -Wdelete-non-virtual-dtor warnings

Base classes should have virtual destructors to
ensure derived classes destructor is also virtual.

This is not a major issue, since in all of the
warning cases there is no base destructor, but
its nice to shutup the compiler warnings.

src/Device.h

@@ -85,6 +85,7 @@ typedef QSharedPointer<Devices> DevicesPtr;
 
 struct Devices
 {
+    virtual ~Devices() {}
     virtual DevicePtr newDevice( CommPortPtr, Device::StatusCallback ) = 0;
 
     // port *might* be supported by this device type implementation:

src/ProtocolHandler.h

@@ -29,7 +29,7 @@
 class ProtocolMessage {
  public:
   ProtocolMessage() { }
-  ~ProtocolMessage() { }
+  virtual ~ProtocolMessage() { }
 
   enum {
     HELLO, HELLOFAIL, HELLOSUCCEED, CLIENTLIST, CLIENT, TELEMETRY,

src/RideFileCommand.h

@@ -46,7 +46,7 @@ class RideFileCommand : public QObject
 
     public:
         RideFileCommand(RideFile *ride);
-        ~RideFileCommand();
+        virtual ~RideFileCommand();
 
         void setPointValue(int index, RideFile::SeriesType series, double value);
         void deletePoint(int index);
@@ -97,7 +97,9 @@ class RideCommand
         enum commandtype { NoOp, LUW, SetPointValue, DeletePoint, DeletePoints, InsertPoint, AppendPoints, SetDataPresent };
         typedef enum commandtype CommandType;
 
+
         RideCommand(RideFile *ride) : type(NoOp), ride(ride), docount(0) {}
+        virtual ~RideCommand() {}
         virtual bool doCommand() { return true; }
         virtual bool undoCommand() { return true; }