modified OpenCL SURF API and the tests in 2.4.x to prove that it gives different from CPU results
made SURF_OCL default constructor parameters the same as SURF
modified SURF's performance test to test OpenCL version as well
fixed doc builder warnings; make sure the tests give reasonable results when OpenCL is not available
Fixed an issue with weight assignment causing the resulting GMM weights to be unsorted in BackgroundSubtractorMOG2
made the example consistent with the fuction definition and improved doc

made the example consistent with the fuction definition and improved doc
remove intel guard since the code is 2 times faster on AMD too
It's will be better
I have changed one sentence in tutorial, making it more understandable
Merge branch '2.4' of git://github.com/Itseez/opencv into mog2_weight_bugfix
Fixed an issue with weight assignment causing the resulting GMM weights to be unsorted in the CUDA and OCL versions of BackgroundSubtractorMOG2
1. fix an error in sample code
2. change an external link to maintain consistency with the previous tutorial
Cut path to CUDA libraries to prevent generation of OpenCVModules.cmake with abs path.
Merge pull request #2473 from euphrat:mog2_weight_bugfix
Merge pull request #2490 from ilya-lavrenov:ocl_sep_filters
Merge pull request #2449 from asmorkalov:cuda_abs_path_fix
switching to CV_HAAR_SCALE_IMAGE mode, enabling test
Libraries filter update after abs path cut.
Merge pull request #2423 from RJ2:bugfix_5
Merge pull request #2400 from RJ2:Bugfix_2