Changed some parameters in 'rbm_tools.py' in order to reduce the running time of 'test_ais.py'.
From now on, test_ais.py can either be run in fast/innacurate mode or slow/accurate mode.
Made code PEP8 compliant
From now on, the script runs using the faster settings when the mode is set to DEBUG_MODE.
Merge pull request #1006 from AlassaneNdiaye/reduce_run_time_test_ais.py

Modifications to the tests in 'pylearn2/tests/rbm/test_ais.py' in order to reduce their running time.