first version of moving KDTree from core to ml
first implementation KNearest wrapper on KDTree
continue fixing nonfree elements
fixed dependency of stitching module on xfeatures2d module as optional
fixed the initModule_xfeatures2d function that was called in module stitching since it is in another namespace than the standard cv one.
Disabled native_sqrt for double, since it may be not implemented and gives compilation error.
Merge pull request #3163 from StevenPuttemans:fix_nonfree_items
OCL: enable clAmdFftGetVersion
fix for cv::memopTypeToStr
Added check AmdFft version to be sure that AmdFft binaries are available
attempt to fix compilation of OpenCL cv::transpose for AMD
Merge pull request #3172 from ilya-lavrenov:tapi_transpose_amd
Merge pull request #3171 from akarsakov:amd_fft_fix
Fixes for compiling with CUDA 6.5

Based on commit feb74b125d7923c0bc11054b66863e1e9f753141 from 2.4.9 branch.
samples: gpu: removed softcascade example

The example in question cannot be compiled anymore as the softcascade
module has been removed in 3858f2291d64652a82fea930ba5c598045633843.
samples: gpu: removed inclusion of non-existent opencv2/contrib/contrib.hpp header, re-introduced TickMeter class in a separate header

This patch removes inclusion of opencv2/contrib/contrib.hpp header,
which does not exist anymore due to removal of opencv_contrib module.

The samples including this header appear to be doing so in order to
use TickMeter class; therefore, the latter is now provided by tick_meter.hpp
header file, located in samples/gpu folder.
samples: gpu: performance: remove inclusion of opencv2/legacy.hpp header

The header is gone now, along with the opencv_legacy module.
samples: gpu: performance: removed FGDStatModel performance comparison test

The FGD background subtraction model was part of opencv_legacy module;
as it is gone now, it makes little sense to benchmark the GPU version,
either, so the whole test is removed.
samples: gpu: super_resolution: disable simple optical flow

The cv::superres::createOptFlow_Simple() function along with the
simple optical flow class implementation is currently commented out
in the superres module's code, so comment it out in the example as well.
samples: gpu: performance: fix include path for opencv_xfeatures2d

As opencv_xfeatures2d is part of opencv-contrib and not opencv repository,
${OpenCV_SOURCE_DIR}/modules/modules/include is not a correct include
path - use ${opencv_xfeatures2d_SOURCE_DIR}/include instead
samples: gpu: performance: BackgroundSubtractorMOG is now part of opencv_bgsegm module
samples: gpu: performance: SURF is now part of opencv_xfeatures2d