Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

Added sample Windows Universal application (UAP) using videoio logic for video preview and processing.
Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

http://code.opencv.org/issues/2206,
http://code.opencv.org/issues/2924

use _mm_sad_epu8 instead of _mm_movemask_epi8 in countNonZero. Therefore, we do not need any popcount table and this solves http://code.opencv.org/issues/4333

http://code.opencv.org/issues/4124

avoid possible problems with zero values in tone mapping algorithms (http://code.opencv.org/issues/4020)

added test to prove that remap does not leak memory (http://code.opencv.org/issues/2502). disabled the test for now to save execution time.

significantly improved parallel non-local means by using granularity parameter in parallel_for_ loop. Because the algorithm deals with sliding sums, it's essential that each thread has enough work to do, otherwise the algorithm gets higher theoretical complexity and thus there is no speedup comparing to 1-thread code (at best).

increased singularity epsilon in LU decomposition. This solved singular case from http://code.opencv.org/issues/3305. Added the respective test.

added support for n-channel (n>4) images in warpAffine/warpPerspective/remap: http://code.opencv.org/issues/4190

Avoid clearing HaarEvaluator::tofs variable (introduced fb8478eb) in HaarEvaluator::setImage(...) since it won't be recomputed by HaarEvaluator::computeOptFeatures() for cases where the input image dimensions and requested search scales are the same as the previous.  If none of the above change then it should be correct, and if they do change it will be computed correctly inside HaarEvaluator::computeOptFeatures() (in commit 952f9dbe)

I'm guessing there is a unit test for this that needs to be called 2x with the same image and search parameters (or another image with the same size) to illustrate the problem.