Merge branch 'hotfix/0.9.10'
yay rst!
Merge README change from franch 'master' into develop
Merge branch 'develop' of github.com:EducationalTestingService/skll into develop
Updated .gitignore to after tests folder reorganization to ignore temporary testing files.
Slight refactoring of Learner._create_estimator to simplify adding new estimators, and make it so people can override the kernel for SVR and RescaledSVR.