Sim spice fix: the frame size was not the last stored size (like for other frames) but a default fixed value.

The frame size (and its subframes) is now the last used.

eeschema/sim/sim_plot_frame.cpp

@@ -203,8 +203,6 @@ SIM_PLOT_FRAME::SIM_PLOT_FRAME( KIWAY* aKiway, wxWindow* aParent )
     // instead of being behind the dialog frame (as it does)
     m_settingsDlg = NULL;
 
-    SetSize( ConvertDialogToPixels( wxSize( 400, 300 ) ) );
-
     // resize the subwindows size. At least on Windows, calling wxSafeYield before
     // resizing the subwindows forces the wxSplitWindows size events automatically generated
     // by wxWidgets to be executed before our resize code.