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

plugins/samplesource/plutosdrinput/plutosdrinput.cpp

@@ -58,6 +58,11 @@ PlutoSDRInput::~PlutoSDRInput()
     resumeBuddies();
 }
 
+void PlutoSDRInput::destroy()
+{
+    delete this;
+}
+
 bool PlutoSDRInput::start()
 {
     if (!m_deviceShared.m_deviceParams->getBox()) {

plugins/samplesource/plutosdrinput/plutosdrinput.h

@@ -76,6 +76,7 @@ public:
 
     PlutoSDRInput(DeviceSourceAPI *deviceAPI);
     ~PlutoSDRInput();
+    virtual void destroy();
 
     virtual bool start();
     virtual void stop();