Voronoi(Worley) and Marble

Added marbleMaya node grabbed from 3Delight.
Replaced Worley node with 3 separate Voronoi3D nodes: calculating
euclidian, manhattan distance and both. Unlike old Worley node, the new
ones outputs all the data: F1, P1, F2 and P2 (and not only F1 like
Worley did).
Collected all the Voronoi nodes into the folder.