Merge branch 'release/0.9.15' into develop
Fixed an issue with PDF documentation building via sphinx.
fixed summary output for ablation experiments
Fixed a bug in run_ablation pertaining to the scenario where
featureset_name was not specified in the config file.
Just added a little bit to ignore some pylint messages.
Properly enforced the requirement that 'featuresets' is a list of
lists and 'featureset_names' is a list of strings. Modified example
and test config files to conform to this requirement. Added unit test
for ablation. Also modified run_ablation to put any generated cfg files
in the same directory as the original cfg file.
Fixed a typo in test_skll.py.
Merge branch 'develop' into feature/summaries_for_ablation
Merge branch 'develop' of github.com:EducationalTestingService/skll into develop
Merge branch 'feature/summaries_for_ablation' into develop

Conflicts:
	skll/experiments.py
Updated changelog and bumped version to 0.9.16
Merge branch 'release/0.9.16'