Closing test coverage gap

- Modified `experiments.py` to make sure that we reject parsing config files with no `task` and `experiment_name`
- Added 3 tests to test config file parsing, to start with
- Added config file template for these tests
Only the first line of word-wrapped docstrings show up when you run `nosetests -v`, so you either want to make these shorter, or just turn them into `#` comments (and just let the function name be the name of the test).