* issue-16736: quick step towards moving SIFT from non-free to free. Moves
include, tests, and implementation to free area.

* FREAK : better rounding off for weighted dx and dy of orientation pairs

* updated using cvRound

* cvRound modified

* Add overload method and fix typos in omnidir (1/2)

Addresses part of https://github.com/opencv/opencv/issues/16601

* Add overload method in omnidir (2/2)

Addresses part of https://github.com/opencv/opencv/issues/16601

videostab: Fix out of range data usage

* videostab: Add simple UTs for video stabilizers

Reproduces issue #5178

* videostab: Fix out of range data usage

Fixes issue #5178

* videostab: Use cv::Range for ranges instead of std::pair

Add python bindings to cudaobjdetect, cudawarping and cudaarithm

* Overload cudawarping functions to generate correct python bindings.
Add python wrapper to convolution funciton.

* Added shift and hog.

* Moved cuda python tests to this repo and added python bindings to SURF.

* Fix SURF documentation and allow meanshiftsegmention to create GpuMat internaly if not passed for python bindings consistency.

* Add correct cuda SURF test case.

* Fix python mog and mog2 python bindings, add tests and  correct cudawarping documentation.

* Updated KeyPoints in cuda::ORB::Convert python wrapper to be an output argument.

* Add changes suggested by alalek

* Added changes suggested by asmorkalov

* fixed typo

* fixed document

new module: intensity_transform (includes gamma correction, log transfomration, autoscaling, contrast stretching)

build error fix: remove trailing whitespaces, casting types

minor edits based on alalek's feedback

removing trailing whitespace

using std::array for LUT argument

Fixes error occurs in cv::ppf_match_3d::ICP::registerModelToScene()

* corrected out of range error

* remove unnecessary changes

* fix warning

Fixed KinFu getCloud() at empty volume

* KinFu getCloud(): an empty volume check added to OCL code

* minor

Update test_hdr.cpp

Update test_hdr.cpp

Remove not used dependency.
Fix some warnings reported by VS2017.

* cuda_mog2_issue_5296
original commit: https://github.com/opencv/opencv/commit/5bf73457431b7d2cb87ac8c107865388dbf66642