Refactor experiments.py to limit number of concurrent processes being spawned, and consolidate ablation code. Also only loads each featureset once now.
Move gridmap warning back to run_configuration, and remove parallel mode from run_experiment with multiple configuration files, since that's no longer necessary.
Separate out what used to be _parse_config_file into _setup_config_parser to simplify unit tests.
Make run_experiment use new experiments API.
Switch back to loading each feature set within _classify_featureset to speed up gridmap jobs substantially.
Fix issue where ablated_features column wasn't being added to summary files.
Make summarize_results pass an integer for _write_summary_file ablation argument.
Merge branch 'feature/refactor_experiments' into develop