added supports of 4-channels image to gpu::minMax and gpu::cvtColor for RGB <-> YCrCB, RGB <-> YUV and RGB <-> XYZ color conversion.

disabled gpu::sum, gpu::minMax, gpu:Canny until fix crash.

fixed FernDescriptorMatch; optimized keypoint regions matching in detector/descriptor evaluation; added CalonderDescriptorExtractor to evaluation tests

possible fix for ticket 380 (should not hurt camera calibration engine, as the fix only affects non-planar objects)

minor fix of matrix_operations.cpp.

added calib3d dependency of highgui, to visualize checkerboard detector work, and probably other algorithms

added RGB <-> XYZ color conversion.
gpu morphology minor fix.