added a unit test to make sure skll does not crash in cross-validation when there are rare classes that might only show up in a test fold
merged the latest develop branch, cleaned up unused imports
fixes for CV with rare classes: separated out creation of label dictionaries, added warnings, etc.
Initial add of conda.yaml file
Removed build string from conda.yaml
Iris configuration file walk-through.
Add back missing entry points and add back build string.
Merge pull request #173 from EducationalTestingService/feature/conda-yaml

Initial add of conda.yaml file
Merge branch 'develop' into feature/fix_for_cv_with_rare_classes
Merge branch 'develop' into feature/configurable_grid_folds