Created nengo_testing branch.

Created nengo_testing branch and added updated test_array.py class. New testing class will be based of python unittests.
Refactored test code.

Removed old nef-py test code. Created new test code for Model, Network, Ensemble, Node, Connection, Filter, LearningRate, NeuronModel objects.
Updated ensemble test.

Added advanced test framework and possible unittest framework.
Added one advanced test example.

Updated ensemble test code to include framework for adding advanced tests to the testcase framework.