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/image.h

@@ -254,6 +254,20 @@ public:
             Handler name.
     */
     void SetName(const wxString& name);
+
+    /**
+        Retrieve the version information about the image library used by this
+        handler.
+
+        This method is not present in wxImageHandler class itself but is
+        present in a few of the classes deriving from it, currently
+        wxJPEGHandler, wxPNGHandler and wxTIFFHandler. It returns the
+        information about the version of the image library being used for the
+        corresponding handler implementation.
+
+        @since 2.9.2
+     */
+     static wxVersionInfo GetLibraryVersionInfo();
 };