Implement TimeSeriesBisectingKMeans

[adagrad]

Is your feature request related to a problem? Please describe.
Classical hierarchical clustering approaches requiring a distance matrix are far too resource intense for a lot of samples. Thus scikit learn has introduced the BisectingKMeans. However, there I cant use the dtw distance metric

Describe the solution you'd like
It would be really great to more or less copy the scikit implementation following the
TimeSeriesKMeans API. PS If you are really nice you could add an easier way to access the hierarchy as scikit does.

[nilesh05apr]

@adagrad i would like to work on BisectingKMeans algorithm implementation same as scikit learn has.

[rtavenar]

@nilesh05apr great!

Feel free to open a PR and ask for help at any point!