call OnInit() from all samples to allow using standard command line options with all of them (patch 1623971)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@44354 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/memcheck/memcheck.cpp

@@ -56,6 +56,9 @@ IMPLEMENT_APP(MyApp)
 // `Main program' equivalent, creating windows and returning main app frame
 bool MyApp::OnInit(void)
 {
+  if ( !wxApp::OnInit() )
+	  return false;
+
   // Create the main frame window
   MyFrame *frame = new MyFrame((wxFrame *) NULL);