added CV_16SC2 && CV_16UC1 map types support to ocl::remap (INTER_LINEAR mode)
added ROI support to ocl::buildWarp*Maps functions
added an accuracy test for ocl::buildWarpPerspectiveMaps
fixed ocl::cvtColor for CV_YUV2BGRA and CV_YUV2RGBA
added YCrCb to RGB, BGR, RGBA, BGRA modes to ocl::cvtColor
color.cpp refactoring: created generic interface for toRGB and fromRGB callers
added RGB -> XYZ conversion to ocl::cvtColor
added XYZ to RGB conversion to ocl::cvtColor
added RGB[A] <-> BGR[A] conversion to ocl::cvtColor
added RGB5x5 <-> RGB conversion
added a performance test for ocl::buildWarpPerspectiveMaps; moved warps to a separate file
Fixed the "image sequence" capture not failing when a pattern isn't found.

at can't be a null pointer, so the condition was always false, and
a nonsensical pattern like "image.png%00d" was being inferred.
removed 2000x2000, 4000x4000 from test sizes of ocl::adaptiveBilateralFilter
added RGB5x5 <-> Gray
Merge pull request #1783 from SpecLad:cap-no-pattern
Merge pull request #1773 from ilya-lavrenov:ocl_buildWarpPerspectiveMaps
Merge pull request #1766 from ilya-lavrenov:ocl_remap_linear
Merge pull request #1782 from ilya-lavrenov:ocl_adapBilat
Merge pull request #1775 from ilya-lavrenov:ocl_cvtColor