core: fix MatExpr::size() for gemm()

* core(test): MatExpr::size() test for gemm()

* core: fix MatExpr::size() for gemm()

* Ignore clang warnings for deprecated enum+enum operations in mat.inl.hpp

* build: added customization macros, cmake flags for OpenCV build

V4L2: Add V4L2_PIX_FMT_Y12 (12 bit grey) support

* Vectorize calculating integral for line for single and multiple channels

* Single vector processing for 4-channels - 25-30% faster

* Single vector processing for 4-channels - 25-30% faster

* Fixed AVX512 code for 4 channels

* Disable 3 channel 8UC1 to 32S for SSE2 and SSE3 (slower).  Use new version of 8UC1 to 64F for AVX512.

in sample codes instead of cpp files' name.

removed all the changes occured while trying to resolve conflicts

* Custom layers with nGraph

* nGraph: multiple outputs from nodes

* Fixed getCPUCount

Minor new line changes

Android fix | efficient linux checks

Android fix 2

Fixed cpu logic for non linux platforms

Android fix 3

Android fix 4

* No v1 case handle | Refactor long lines

* Refined Cgroups logic | Combine Android and Linux

* Fixed directives

* Added support for --cpus | Fixed minor bug in Andriod | Change file read logic

* Added macro checks for apple errors

* Fixed macro to include android

* Addressed review comments

* Fixed android macro

* Refined return values

* Fixed apple warning

* Addressed review comments

* Fixed whitespace

* Android Fix try 1

* Android Fix try 2

* Android Fix try 3

* Removed unwanted endif

* Android Fix try 4

* Android Fix try 5

* Macro Restructure

* core: updates to CPUs detection (minor)

* Update to new ICV packages

MacOS ia32 ICV package is no longer built.

* cmake(ippicv): add Apple 32-bit check

* Updated commit hash

* add  python version of video-input-psnr-ssim

* remove ret

* documentation changes

* added link for python file

* command line argument

* dnn: fix processing of input shapes

- importer: avoid using of .setInput() => .setInputShape()
- setInput: shape limitation check (partial)

* dnn(test): test .setInput() in readNet()

fixed the ordering of contour convex hull points

* partially fixed the issue #4539

* fixed warnings and test failures

* fixed integer overflow (issue #14521)

* added comment to force buildbot to re-run

* extended the test for the issue 4539. Check the expected behaviour on the original contour as well

* added comment; fixed typo, renamed another variable for a little better clarity

* added yet another part to the test for issue #4539, where we run convexHull and convexityDetects on the original contour, without any manipulations. the rest of the test stays the same