Add more distance functions

[doxakis]

It would be great to have more distance functions ready to use.

The python lib implements lot of metrics. http://hdbscan.readthedocs.io/en/latest/basic_hdbscan.html#distance-matrices

The following file expose distance functions: https://github.com/scikit-learn-contrib/hdbscan/blob/master/hdbscan/dist_metrics.pyx

Some distance functions:

• Chebyshev Distance
• Minkowski Distance
• W-Minkowski Distance
• Mahalanobis Distance
• Hamming Distance
• Canberra Distance
• Bray-Curtis Distance
• Jaccard Distance
• Matching Distance
• Dice Distance
• Kulsinski Distance
• Rogers-Tanimoto Distance
• Russell-Rao Distance
• Sokal-Michener Distance
• Sokal-Sneath Distance
• Haversine Distance (2 dimensional)
• Yule Distance

In the following folder: HdbscanSharp/Distance/ There is some examples. (For example, see ManhattanDistance) It must implements IDistanceCalculator.

If there is some limitation, it can throw a meanful exception with explications. For example, if the distance works only for 2 dimension, throw an exception.

I suggest to add one class for each new distance function and add minimal documentation (Description, formula and suggested use case if any. Check wikipedia).