Web API: fixed segfault when mixing start/stop between GUI and API. Applied to BladeRF input, SDRdaemon input and SDRPlay

plugins/samplesource/bladerfinput/bladerfinput.h

@@ -74,7 +74,26 @@ public:
         { }
     };
 
-	BladerfInput(DeviceSourceAPI *deviceAPI);
+    class MsgStartStop : public Message {
+        MESSAGE_CLASS_DECLARATION
+
+    public:
+        bool getStartStop() const { return m_startStop; }
+
+        static MsgStartStop* create(bool startStop) {
+            return new MsgStartStop(startStop);
+        }
+
+    protected:
+        bool m_startStop;
+
+        MsgStartStop(bool startStop) :
+            Message(),
+            m_startStop(startStop)
+        { }
+    };
+
+    BladerfInput(DeviceSourceAPI *deviceAPI);
 	virtual ~BladerfInput();
 	virtual void destroy();