Feature Request: Include sklearn.preprocessing.QuantileTransformer

[saffrydaffry]

QuantileTransformer is useful for scaling data whilst being robust to outliers. I didn't see this class listed in the documentation for convertibility to pmml. Just curious if there are plans to include it?

The sklearn docs:
http://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.QuantileTransformer.html#sklearn.preprocessing.QuantileTransformer

Thank you!

[liubinpoem]

If the author write a step by step tutorial on guiding how to develop customized function, this kind of problem will be solved much easier. And it will also help the develop of this project.