Fix plugin error handling for wx3.0 on Windows

This prevents a PCSX2 lock up that requires Task Manager to kill. It
seems the messagebox intercepts the GSframe's close event, hides itself
and then leaves you with no way of ending PCSX2 normally. So close the
GS frame before the message box appears.

pcsx2/gui/AppMain.cpp

@@ -660,10 +660,23 @@ void Pcsx2App::HandleEvent(wxEvtHandler* handler, wxEventFunction func, wxEvent&
 	// ----------------------------------------------------------------------------
 	catch( Exception::PluginOpenError& ex )
 	{
-		// Should need to do much here -- all systems should be in an inert and (sorta safe!) state.
-		
-		Console.Error( ex.FormatDiagnosticMessage() );
-		AddIdleEvent( PluginInitErrorEvent(ex) );
+		// It might be possible for there to be no GS Frame, but I don't really know. This does
+		// prevent PCSX2 from locking up on a Windows wxWidgets 3.0 build. My conjecture is this:
+		// 1. Messagebox appears
+		// 2. Either a close or hide signal for gsframe gets sent to messagebox.
+		// 3. Message box hides itself without exiting the modal event loop, therefore locking up
+		// PCSX2. This probably happened in the BIOS error case above as well.
+		// So the idea is to explicitly close the gsFrame before the modal MessageBox appears and
+		// intercepts the close message. Only for wx3.0 though - it sometimes breaks linux wx2.8.
+#if wxMAJOR_VERSION >= 3
+		if (GSFrame* gsframe = wxGetApp().GetGsFramePtr())
+			gsframe->Close();
+#endif
+		Console.Error(ex.FormatDiagnosticMessage());
+
+		// Make sure it terminates properly for nogui users.
+		if (wxGetApp().HasGUI())
+			AddIdleEvent(PluginInitErrorEvent(ex));
 	}
 	// ----------------------------------------------------------------------------
 	catch( Exception::PluginInitError& ex )