Update link to documentation, use readthedocs.org for automatic documentation builds

Cherry-picked from develop

Author: iMichka

README.rst

@@ -29,7 +29,7 @@ For issues with pygccxml you can open an issue here: https://github.com/gccxml/p
 Documentation
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-For examples and tutorials see the documentation: http://gccxml.github.io/pygccxml/
+For examples and tutorials see the documentation: http://pygccxml.readthedocs.org
 
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