Merge pull request #1 from bluescarni/voronoi

Initial import of the Voronoi grid helper class
Updated to use voronoi_helpers
Remove unused file
Ensure huge assumes correct type in kdtree
Move points to global scope to avoid pointer getting corrupt
Fix bug for cells with neighbors that are cell 0 in Python notation. Also fix intersection with boundaries.
Ensure that random_position_cell cannot stay stuck in an infinite loop