Merge pull request #1886 from ilya-lavrenov:tapi_lut
added OCL-TAPI arithm tests
added cv::pow to T-API
added setIdentity to T-API
added cv::transpose to T-API
added cv::cartToPolar to T-API
added cv::polarToCart to T-API
added cv::compare to T-API
added cv::repeat to T-API (fix for copyTo -> UMat is needed)
added cv::countNonZero to T-API
added cv::sum to T-API
added cv::meanStdDev to T-API
ability to use cv::PSNR with transparent cv::norm