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

Fix typo: 'right direction' to 'y direction' in harris corner detector tutorial.

Improve the readability of the tutorial.

* change tutorial to use enum name instead of value

* use enum name instead of value

Update windows_install.markdown (#8752)

* Update broken downloads link

* Update broken downloads link

* Update broken downloads link

* Extending template_matching tutorial with Java

* adding mask to java version of the tutorial

* adding the python toggle and code

* updating table of content

* adding py and java to table of content

* adding mask to python

* going back to markdown with duplicated text

* non duplicated text

Corrected the spelling which was used in explanation for parameters.

https://www.mathjax.org/cdn-shutting-down/#alternative-cdn-providers

New p3p algorithm (accepted by CVPR 2017) (#8301)

* add p3p source code

* indent 4

* update publication info

* fix filename

* interface done

* plug in done, test needed

* debugging

* for test

* a working version

* clean p3p code

* test

* test

* fix warning, blank line

* apply patch from @catree

* add reference info

* namespace, indent 4

* static solveQuartic

* put small functions to anonymous namespace

updated links for python, numpy and matplotlib

Fix grammar error in py_features_meaning.markdown (#8378)

* Update linux_install.markdown

Grammar improvements, fixed typos.

* Update tutorials.markdown

Improvements in grammar.

* Update table_of_content_calib3d.markdown

* Update camera_calibration_square_chess.markdown

Improvements in grammar. Added answer.

* Update tutorials.markdown

* Update erosion_dilatation.markdown

* Update table_of_content_imgproc.markdown

* Update warp_affine.markdown

* Update camera_calibration_square_chess.markdown

Removed extra space.

* Update gpu_basics_similarity.markdown

Grammatical improvements, fixed typos.

* Update trackbar.markdown

Improvement for better understanding.

0 corresponds to FLANN_INDEX_LINEAR

0 corresponds to FLANN_INDEX_LINEAR

Add initialisations to make clear what values actually have to be passed.

Moreover, in accordance with https://github.com/opencv/opencv/blob/383559c2285baaf3df8cf0088072d104451a30ce/modules/flann/include/opencv2/flann/defines.h#L68, I believe `FLANN_INDEX_KDTREE` was being initialised wrongly in the code examples, 1 should be correct, whereas 0 is `FLANN_INDEX_LINEAR`.

cv2.findContours() no longer modifies source image (#8150)

* cv2.findContours() no longer modifies source image

Since OpenCV 3.2, cv2.findContours() no longer modifies the source image but returns a modified image as the first of three return parameters.  ??? Do I have that correct ???

Also fixed up the code blocks to be valid markdown.

* ```python --> @code{.py}

Enables syntax highlighting in docs.

- disabled OPTIMIZE_OUTPUT_JAVA
- filtered out *.m scripts
- removed link to old Sphinx documentation
- replaced all mentions of Sphinx with Doxygen

Fixed exceptions, print statements, and long types for gen_pattern.py to be Python 3 compatible (#7994)

* fixed exceptions and print statements to be python 3 compatible; removed long type checks (py3 uses int); whitespace reformatting

* Pulled latest svgfig from upstream

https://github.com/jpivarski/svgfig/commit/f3179a8926508bf0f9021fd4e1f9731c95524a38

Use directly the doxygen snippet command for the Changing the contrast and brightness of an image tutorial. Extend the tutorial with a pratical example and with a gamma correction method to adjust the brightness of an image.

Fix Documentation Typos (#7942)