to control DNN_BACKEND_DEFAULT enumeration value behavior

`camid` value is always -1 after close().

* setTo_#10507

* setTo_Nan_10507

* setTo: update check / test for NaNs

Add Java and Python code for the following imgproc tutorials: Finding contours in your image, Convex Hull, Creating Bounding boxes and circles for contours, Creating Bounding rotated boxes and ellipses for contours, Image Moments, Point Polygon Test.

Improve experience of launching app from explorer:
- application just flash (open/close) the console window
Suggested Win32 application flavor additionally shows MessageBox
and waits for User interaction.

64-bit only

- build "opencv_version" only: `cmake -DBUILD_APPS_LIST=version ...`
- option 'BUILD_opencv_apps' should be 'ON'

- no behavior changes in grabFrame()
- added Lock2D() support into retrieveFrame()

Add LD_PRELOAD instruction to be able to run Java code that calls OpenCV functions that use the Intel MKL library.

- show capturing information: width / height / fps
- show average FPS for cap.read()+imshow() via cv::getTickCount()
- optional frame processing code path

- use cv::getTickCount() instead of Win32 GetTickCount()
- process message queue before timeout exit

dnn: Fix output mismatch when forward dnn model contain [depthwise conv(group=1) + bn + prelu]  (#11649)

* this can make sure [depthwise conv(group=1) + bn + prelu] output not shift

* add TEST to show the output mismatch in [DWconv+Prelu]

* fix typo

* change loading image to init cvMat directly

* build runtime model, without loading external model

* remove whitespace

* change way to create a cvmat

* add bias_term, add target output

* fix [dwconv + prelu] value mismatch when no optimizations

* fix Test error when change output channels

* add parametric test

* change num_output to group value

* change conv code and change test back