Add wrapper in MDArray for class cern.colt.matrix.tdouble.algo.DoubleStencil

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Stencil operations. For efficient finite difference operations. Applies a function to a moving 3 x 3 or 3 x 3 x 3 window. Build on top of matrix.zAssignXXXNeighbors(...). You can specify how many iterations shall at most be done, a convergence condition when iteration shall be terminated, and how many iterations shall pass between convergence checks. Always does two iterations at a time for efficiency. These class is for convencience and efficiency.