Implement the following unit test

[mfeurer]

A good unit test would consist of the following steps:

1. instantiate a classifier
2. solve a small task with a complex decision boundary
3. upload the classifier to OpenML (not necessarily the run result)
4. download the flow from OpenML and re-instantiate the classifier
5. solve the same small task as in step 2
6. assert that the predictions from the classifier before uploading are exactly the same as the predictions from the re-instantiated classifier

Courtesy to @janvanrijn on https://github.com/openml/OpenML/wiki/Flow-Serialization