Create `train`, `test` and `output` sub-directories before running tests
Create `train`, `test` and `output` sub-directories before running tests

- Added a module level `setup()` function that creates the three subdirectories before any tests are run.
- Modified `fill_in_config_paths()` to only fill in the paths and not do any directory creation.

ernfrid/skll,ernfrid/skll