Add constructors taking initializer_list for some of OpenCV data types (#9034)

* Add a constructor taking initializer_list for Matx

* Add a constructor taking initializer list for Mat and Mat_

* Add one more method to initialize Mat to the corresponding tutorial

* Add a note how to initialize Matx

* CV_CXX_11->CV_CXX11

imgproc: fix MORPH_HITMISS operation when kernel has no negative values

Add gstreamer capture capability for some YUV formats (#8914)

* Add gstreamer capture capability for some YUV formats.(only for gstreamer-1.0)

* avoid cross initialization error

* add checking if pipeline is manualpipeline, for compatibility.

fix the MSER history's size issue (#8910)

* simplify growHistory and merge

* add assertion for history's size

* MSER: fix merging components' history

Added tests for ResNet-50 and SqueezeNet v1.1

cpu dispatch(core): hamming

AVX optimized implementation of separable filters migrated

AVX and SSE4.1 optimized conversion migrated

AVX and SSE4.1 optimized implementation of resize and warp functions migrated

core: get rid of OPENCV_NOSTL definition

Fix typo in harris corner detection tutorial.

fixed problem in concat layer by disabling memory re-use in layers with multiple inputs

trying to fix the tests when Halide is used to run deep nets

another attempt to fix Halide tests

see if the Halide tests will pass with concat layer fusion turned off

trying to fix failures in halide tests; another try

one more experiment to make halide_concat & halide_enet tests pass

continue attempts to fix halide tests

moving on

uncomment parallel concat layer

seemingly fixed failures in Halide tests and re-enabled concat layer fusion; thanks to dkurt for the patch

AVX optimized implementation of haar migrated to separate file

It is configurable via OPENCV_CPUFEATURES_TARGET_NAME variable

dshow: Only show debugging messages if environment variable OPENCV_DSHOW_DEBUG is explicitly set to non-zero

Based on discussion at: https://github.com/opencv/opencv/pull/9051