Propagate calculated Gaussian kernel size(ref). Otherwise, ipp_GaussianBlur will fail if user doesn't specify a kernel size. (#10579)

- fix Javadoc:
  - generate Javadoc after gather step to process all Java files (including Android 21)
  - generate into 'OpenCV-android-sdk' directly without additional copy step
- use smart copy/move utility functions ('shutil' doesn't well with existed destination)
- by default move files to reduce pressure on storage I/O (> 800Mb)

- fix imports override.
  Problem is observed with BoostDesc.

- add Ptr<> handling (constructor is protected from other packages).
  Observed in ximgproc:
      Ptr<StereoMatcher> createRightMatcher(Ptr<StereoMatcher> matcher_left)"
  where, "StereoMather" is from another package (calib3d)

intermediate commit (to simplify code review)

Adding capability to parse subsections of a byte array in Java bindings (#10489)

* Adding capability to parse subsections of a byte array in Java bindings. (Because Java lacks pointers. Therefore, reading images within a subsection of a byte array is impossible by Java's nature and limitations. Because of this, many IO functions in Java require additional parameters offset and length to define, which section of an array to be read.)

* Corrected according to the review. Previous interfaces were restored, instead internal interfaces were modified to provide subsampling of java byte arrays.

* Adding tests and test related files.

* Adding missing files for the test.

* Simplified the test

* Check was corrected according to discussion. An OutOfRangeException will be thrown instead of returning.

* java: update MatOfByte implementation checks / tests

v2: fix stray trailing whitespace

v3: only allow for up to one property window at the time

Opening multiple windows in the same process will just confuse
the camera filter or outright crash.

Suggested-by: @alalek

Also return whether a dialog was opened at the time.

* UMat blobs are wrapped

* Replace getUMat and getMat at OpenCLBackendWrapper