test and fix examples in various scenarios.

[adhamhashibon]

e.g., the simphony-osp/examples/assertional_knowledge.py fails when the user has multiple name spaces loaded and adding superclasses which also have attributes (e.g., memo and foaf) leading to failure of execution:

The code in simphony-osp/simphony_osp/ontology/individual.py:933 basically is not able to deal with such cases, even though only one attribute is actually used.