Speed up the sample progress dialogs in the sample

Just make them finish faster, it's too boring to wait for them to do it
when testing when they take so long.

samples/dialogs/dialogs.cpp

@@ -2785,7 +2785,7 @@ void MyFrame::DoShowProgress(wxGenericProgressDialog& dialog)
             dialog.Resume();
         }
 
-        wxMilliSleep(200);
+        wxMilliSleep(100);
     }
 
     if ( !cont )
@@ -2817,7 +2817,7 @@ void MyFrame::ShowAppProgress( wxCommandEvent& WXUNUSED(event) )
     {
         progress.SetValue(i);
 
-        wxMilliSleep(500);
+        wxMilliSleep(200);
     }
 
     wxLogStatus("Progress finished");