added call to _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG) | _CRTDBG_LEAK_CHECK_DF) for

VC++: it gives at the end of the program report about memory leaks if any
similar to the one produced by the wxwin memory diagnostic classes (but it
works without problems with VC++ and costs nothing to add)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@457 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775