add python sample

* issue-2060: implement ability to return scores for edgeboxes implementation

* issue-2060: address feedback to add some foolproofing

* doc: fix return parameter for void method

* docs: add missing parameter description

* added detection of inverted Markers, tests included

* corrections added, default preserved, identation, var, comment

Move background subtraction python tutorial to proper location (#2120)

* add tutorial from OpenCV-Python Tutorials

* remove trailing whitespace

* remove MOG2 part

* add cross-link to MOG2 tutorial

Incomplete sentence corrected. Resolves Issue #1997 (#2000)

* Incomplete sentence corrected. Issue #1997 

Resolves Issue #1997

``` FaceRecognizer::train(InputArrayOfArrays src, InputArray labels); ```

The type `InputArray` can accept `vector<T>` or `Mat` types as mentioned here: https://docs.opencv.org/3.4/d4/d32/classcv_1_1__InputArray.html

* Trailing whitespaces problem resolved

* fix rectifyPatch bug when patch orientation is not extracted

avoid broken min/max macros from tesseract headers

If the disparity maps have the depth CV_32F, they are wls-filtered
in `DisparityWLSFilterImpl::filter` but the result is not saved in the
OutputArray of the method. Now, the result is copied to that array.

or with batch rendering