Summary:
These are all essentially no-op changes which allow for nose-style (or pytest-style) test discovery.
With this patch, you can use any of these methods to discover and run tests under `caffe2/python`:
```
python -m unittest discover -p '*test*.py' caffe2/python/
python -m nose caffe2/python/
python -m pytest caffe2/python/
```
Future work:
* Get all of the tests to pass
* Some seem to be testing operations which don't have GPU implementations
* I get a segfault unless I set `CUDA_VISIBLE_DEVICES=0`
* Some tests are flaky
* Allow test discovery throughout the whole project (e.g. the `experiments/` dir)
Closes https://github.com/caffe2/caffe2/pull/199
Reviewed By: pietern
Differential Revision: D4704504
Pulled By: Yangqing
fbshipit-source-id: 8f5687ec9c8aa873dfaff30dbf44272bc38a206b
