moved mulSpectrums, dft and convolve to gpuarithm
gpuimgproc module for image processing
gpufeatures2d module 2d for feature detection and matching
gpuvideo module for video processing
gpucalib3d module for camera calibration and stereo correspondence
gpuobjdetect module for object detection
removed nv_perf_test (it is a duplicate for perf4au)
removed obsolete headers from gpu module
removed obsolete source files from gpu module
removed unused includes
simplify CMakeLists.txt for gpu module
renamed gpunvidia -> gpulegacy
gpuarithm module fixes
gpuwarping module for image warping
moved gpu nlm to photo module
moved image labeling to gpu module
gpustereo module for stereo correspondence
removed gpuobjdetect module
split gpuvideo onto gpuoptflow and gpubgsegm
fixed compilation issues