Added a destroy virtual method to all source input plugin main classes

plugins/samplesource/bladerfinput/bladerfinput.cpp

@@ -60,6 +60,11 @@ BladerfInput::~BladerfInput()
     m_deviceAPI->setBuddySharedPtr(0);
 }
 
+void BladerfInput::destroy()
+{
+    delete this;
+}
+
 bool BladerfInput::openDevice()
 {
     if (m_dev != 0)

plugins/samplesource/bladerfinput/bladerfinput.h

@@ -73,6 +73,7 @@ public:
 
 	BladerfInput(DeviceSourceAPI *deviceAPI);
 	virtual ~BladerfInput();
+	virtual void destroy();
 
 	virtual bool start();
 	virtual void stop();