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
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.
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
kernel warnings on AMD