StereoSGBM -> pointer miscalculation Line 416-419 (Bug #2201)

StereoSGBM allocates a buffer in lines 374-376, which gets (and needs to get) very large when you use the 8-direction Version with large images and disparity ranges. This large buffer is then partioned into a number of arrays. In order to ease requirements for gigabytes of contiguous heap space a bit, I modified the code to have the arrays allocated individually.

Doing so, I get heap corruption after line 419 (release version) on the array pointed to by PixDiff, which I attribute to the original code, not to my changes. In the preceeding 4 lines somehow there are the same variables used for C pointer aritmetics on shorts and for byte pointer arithmetic for memset. Somewhere there a multiplication with sizeof CostType is missing. I stopped analysis here, because the original writer of the code might be much faster in fixing the bug.

My modifications are in the attached file just for information about what I did when the heap error showed up. I don't think this file is necessary or useful for anything else. But line numbers in this ticket refer to the original code.