Merge branch 'feature/fix_unit_tests' into feature/feature_file_ordering
added support for merging featuresets with IDs in different orders
removed assertion that features not be None in FeatureSet initializer
Merge branch 'feature/fix_unit_tests' into feature/feature_file_ordering

Conflicts:
	tests/test_skll.py
Merge branch 'feature/fix_unit_tests' into feature/feature_file_ordering
fixed bug in FeatureSet merging.  made the related unit test better
Merge branch 'develop' into feature/feature_file_ordering

Conflicts:
	tests/test_skll.py
switched to using numpy.testing methods where possible, code formatting
Merge pull request #177 from EducationalTestingService/feature/feature_file_ordering

Allow feature files to be merged regardless of order