Faster k-means

[Arkoniak]

As a future step after the implementation of point-wise parallel computations, it would make sense to improve algorithm by using "Fast kmeans" techniques.

Several approaches exists, here is some inspirational links

• http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=00D8EFB07FE09CFEE6BA1817CDE61A4E?doi=10.1.1.308.1671&rep=rep1&type=pdf
• https://github.com/ghamerly/fast-kmeans
• https://github.com/siddheshk/Faster-Kmeans
• https://arxiv.org/abs/1702.08248

In latter case one should be careful though, there is no license, should contact author whether our MIT is applicable.