use wx/crt.h as the 'official' header for wxCRT wrappers instead of wxchar.h; add comments explaining that users should include wx/crt.h to implementation headers

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46395 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/crt.h

@@ -11,6 +11,11 @@
 #ifndef _WX_CRT_H_
 #define _WX_CRT_H_
 
-#include "wx/wxchar.h"
+// include wxChar type definition:
+#include "wx/chartype.h"
+
+// and wrappers for CRT functions:
+#include "wx/wxcrt.h"
+#include "wx/wxcrtvararg.h"
 
 #endif // _WX_CRT_H_