Fix typos in py_houghlines tutorial.

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

Fix tutorial code link in basic_linear_transform tutorial.

hal_internal.cpp(101): warning C4267: 'initializing': conversion from 'size_t' to 'int', possible loss of data

- added compile check with multiple tries for different configurations
- restored find_package(LAPACK)
- avoided modification of OPENCV_LINKER_LIBS

ml: fix small typo in lr.cpp (#8019)

Fix error usage in HitMiss tutorial, and improved the visualization results (#7978)

* Fix error usage in HitMiss tutorial, and improved the visualization results

Fix error usage in HitMiss tutorial, and improved the visualization results

* Update HitMiss.cpp

* Update HitMiss.cpp

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

Add OpenCV parallel_for_ tutorial.

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.

Add check for all zero moments. If one of the shapes is empty, the match would return zero distance between the shapes even when the other one had content. It now returns DBL_MAX if no moments had value.