#33 Use Combinatorial Number System in VR filtration instead of joins

[jakipatryk]

• introduced a LocalMatrix class serving as somewhat efficient implementation of matrix
• introduced a DistanceMatrix class being a wrapper on top of LocalMatrix with functionality of being constructed from PointsCloud by computing all pairwise distances of points
• implemented Combinatorial Number System (https://en.wikipedia.org/wiki/Combinatorial_number_system) (on steroids)
• reimplemented Vietoris-Rips filtration using the Combinatorial Number System allowing for joins removal for computing combinations
• changed signature of createFiltration a bit to include implicit SparkContext
• moved EuclideanDistanceCalculator to DistanceCalculator companion object
• moved common entities to main package object

Closes #33