Fix severe simulation memory leaks

eeschema/sim/ngspice.cpp

@@ -705,4 +705,10 @@ void NGSPICE::validate()
 }
 
 
+void NGSPICE::Clean()
+{
+    Command( "destroy all" );
+}
+
+
 bool NGSPICE::m_initialized = false;

eeschema/sim/ngspice.h

@@ -97,6 +97,9 @@ public:
     ///< @copydoc SPICE_SIMULATOR::GetNetlist()
     virtual const std::string GetNetlist() const override final;
 
+    ///< @copydoc SIMULATOR::Clean()
+    void Clean() override final;
+
 private:
     void init();
 

eeschema/sim/sim_plot_frame.cpp

@@ -481,6 +481,8 @@ void SIM_PLOT_FRAME::StartSimulation( const wxString& aSimCommand )
     {
         updateTuners();
         applyTuners();
+        // Prevents memory leak on succeding simulations by deleting old vectors
+        m_simulator->Clean();
         m_simulator->Run();
     }
     else
@@ -1641,6 +1643,9 @@ void SIM_PLOT_FRAME::doCloseWindow()
     if( m_simulator->IsRunning() )
         m_simulator->Stop();
 
+    // Prevent memory leak on exit by deleting all simulation vectors
+    m_simulator->Clean();
+
     // Cancel a running simProbe or simTune tool
     m_schematicFrame->GetToolManager()->RunAction( ACTIONS::cancelInteractive );
 

eeschema/sim/simulator.h

@@ -99,6 +99,12 @@ public:
      */
     virtual bool IsRunning() = 0;
 
+    /**
+     * Cleans simulation data (i.e. all vectors) 
+     * 
+     */
+    virtual void Clean() = 0;
+
 protected:
     ///< Model that should be simulated.
     std::shared_ptr<SIMULATION_MODEL> m_simModel;