Merge branch 'release/0.17.1' into develop
Fix crash when modelpath is blank and task is not cross_validate
Clean up and refactor dict_iter functions in skll.data to be iterator classes. Also add some debug logging.
Make nose less verbose and fix missing 'self.' before an attribute in _TSVDictIter.
Update skll_convert to use new API. Fix some issues with _TSVDictIter.
Updated changelog and bumped version to 0.18.0 (because we changed the internal API a bit).
Cleaned up multiprocessing stuff to use concurrent.futures in data module.
Merge branch 'develop' into release/0.18.0
Make travis configuration less redundant.
Merge branch 'release/0.18.0'