Add ocl implementation of the sepFilter2D into img_proc module.
Fix compilation warnings
experimental moments implementation (does not work yet)
moments work now and work more or less fast
tuned the speed for OpenCL-based moments (still slower than the single-thread SSE2 CPU code :( )
hopefully fixed test failures and complains from the doc builder
improved performance of moments (on 720p or larger images)
OCL: included ORB featured detector/descriptor extractor.
added cv::mixChannels to T-API
fixed getUMatIndex
disabled cv::dft opencl impl for CPU devices
some fixes of cv::mixChannels
this commit prevents segfaults in case of opencl disabled
Merge pull request #2076 from ilya-lavrenov:tapi_dft
Merge pull request #2063 from vpisarev:ocl_moments
Merge pull request #2034 from pentschev:ocl_features2d_orb_master
Change sprintf to cv::format, and EXPECT_MAT_NEAR to OCL_EXPECT_MATS_NEAR
Change threshold from 2.0 to 1.0 in the test
added new perf tests to core
Merge pull request #2077 from ilya-lavrenov:tapi_context