optimized sep filter
simplified cv::sepFilter2D OpenCL part
generalized OpenCL version of cv::sepFilter2D; removed some restrictions and added 3-channels support
enabled 3-channels support for cv::createSuperResolution_BTVL1
changed epsilon for test pass on Win32
added 3-channels support to optimized version
added gpu type selection in OPENCV_OPENCL_DEVICE parser
changing default perf strategy from BASIC (old) to SIMPLE (new, faster)
Merge pull request #2503 from mlyashko:optflow_dualtvl1
Merge pull request #2491 from ilya-lavrenov:tapi_sep_filter
Merge pull request #2515 from apavlenko:perf_default_strategy
added 3-channels support to cv::Canny
case-insensitivity
eliminated restriction delta == 0 from cv::sepFilter2D
Merge pull request #2512 from KonstantinMatskevich:ocl_gpu_type_parser
Merge pull request #2522 from ilya-lavrenov:tapi_canny
Merge pull request #2525 from ilya-lavrenov:tapi_sep