BackgroundSubtractorMOG2, learningRate=0 optimization
added performance validation check
Merge pull request #3352 from alucarded:BackgroundSubtractorMOG2_optimization
Added tests for Image2D
Optimize OpenCL version of StereoBM function
Fix problems on NVidia devices.
ocl: restore clFinish() in unmap() for AMD devices

This reverts commit 7d91b8efcd053304e5b0fb5afff06e151b2d4096.
Added extra checks to ocl::Image2D
Merge pull request #3368 from alalek:amd_clfinish
Merge pull request #3284 from vbystricky:oclopt_stereoBM
Move _dst.create() to the begining of scaleAdd function
Merge pull request #3342 from alalek:perf_stability_check
Merge pull request #3367 from akarsakov:ocl_image2d
Merge pull request #3369 from vbystricky:fix_scaleAdd
naive implementation
use local memory
use vectors
Some small fixes
use LOCAL_SIZE+1