Contribution from pklauke , that is: `BlendingOptimizer`.
0.1.7
0.1.6
0.1.5
0.1.4
0.1.3
* toolkit is compatible with [steppy 0.1.2](https://github.com/minerva-ml/steppy/releases/tag/v0.1.2) and above. * added LightGBM implementation to [misc.py](https://github.com/minerva-ml/steppy-toolkit/blob/master/toolkit/misc.py). * some minor refactors.