Add wxVersionInfo and functions returning it for 3rd party libraries.

Add simple wxVersionInfo class holding the version information.

Also add GetLibraryVersionInfo() static method to wx{JPEG,PNG,TIFF}Handler,
wxStyledTextCtrl and wxXmlDocument classes and wxGetZlibVersionInfo() and
wxGetLibraryVersionInfo() global functions using it.

Closes #12690.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66259 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/utils.h

@@ -145,10 +145,19 @@ void wxBell();
     doesn't otherwise handle this event.
 
     @since 2.9.0
-
+    @see wxGetLibraryVersionInfo()
     @header{wx/utils.h}
 */
-void wxInfoMessageBox(wxWindow parent = NULL);
+void wxInfoMessageBox(wxWindow* parent);
+
+/**
+    Get wxWidgets version information.
+
+    @since 2.9.2
+    @see wxVersionInfo
+    @header{wx/utils.h}
+*/
+wxVersionInfo wxGetLibraryVersionInfo();
 
 //@}