* Seeding should be done through unittest_tools.set_seed
** seeds with THEANO_UNITTEST_SEED env. var if it is present
** if env. var is not present, it will use the seed provided by the user
** if user provided no seed, it will seed with None (random seed)
* when creating RandomState objects, the parameter should be the return value of
fetch_seed() which will try to get the env. var. seed, if not default to the
user value or None.

* Fixed 2 tests in test_basic which had been hardcoded for a specific seed