Fix processing of pending events in mixed MFC/wx applications

ProcessPendingEvents() was never called when using MFC event loop,
meaning that queued events were never processed, so that using
CallAfter() didn't work.

Fix this and also ensure that these events are processed soon enough by
also implementing WakeUpIdle() for such applications, as wxWakeUpIdle()
didn't do anything neither for them.

include/wx/msw/mfc.h

@@ -113,8 +113,13 @@ public:
     {
         BOOL moreIdle = BaseApp::OnIdle(lCount);
 
-        if ( wxTheApp && wxTheApp->ProcessIdle() )
-            moreIdle = TRUE;
+        if ( wxTheApp )
+        {
+            wxTheApp->ProcessPendingEvents();
+
+            if ( wxTheApp->ProcessIdle() )
+                moreIdle = TRUE;
+        }
 
         return moreIdle;
     }
@@ -172,6 +177,17 @@ public:
         // instead.
         ::PostQuitMessage(0);
     }
+
+    void WakeUpIdle() wxOVERRIDE
+    {
+        // As above, we can't wake up any wx event loop, so try to wake up the
+        // MFC one instead.
+        CWinApp* const mfcApp = AfxGetApp();
+        if ( mfcApp && mfcApp->m_pMainWnd )
+        {
+            ::PostMessage(mfcApp->m_pMainWnd->m_hWnd, WM_NULL, 0, 0);
+        }
+    }
 };
 
 #endif // _WX_MSW_MFC_H_