Archive the project

Since `pydot` has been moved to `pydot` organisation
its development can be revived and no there is no need
to keep `pydot-ng` alive (again).

README.rst

@@ -1,5 +1,9 @@
-pydot - Python interface to Graphviz's Dot language
+pydot-ng - Python interface to Graphviz's Dot language
+------------------------------------------------------
+
+Archived. Please use https://github.com/pydot/pydot
 ---------------------------------------------------
+
 Ero Carrera (c) 2004-2007
 
 ero@dkbza.org