Bug fixes:
* Predefined feature sets included a top-hat-filtered image and thus, tended to consider local intensity differences. This feature has been removed from the feature set.
New features:
* Custom-feature definitions can be entered as string
* The list of predefined feature sets has been extended.
See the full list of predefined features and how to make custom feature sets here:
https://github.com/haesleinhuepf/oclrfc/blob/master/demo/feature_stacks.ipynb