modified BackgroundSubtractorMOG2::getBackgroundImage so that it can now work with gray-level images.
Merge branch '2.4' of git://github.com/Itseez/opencv into mog2_bgimg_gray
made a performance improvement.
changed the way the mean value for each pixel is assigned in the output image.
Merge pull request #2509 from euphrat:mog2_bgimg_gray