Adding of destructor and placement new constructors for classes wrapped with CV_EXPORTS_W_SIMPLE macro

cosmetic changes to fix this warning.
real bugs not found

(cherry picked from commit 408107ce)

(cherry picked from commit 3934d61d)

(cherry picked from commit 32d7c195)

Backport of mariusmuja/flann@f8ca6df3.

Backport of mariusmuja/flann@f8ca6df3.

Conflicts:
	modules/contrib/include/opencv2/contrib/retina.hpp

Current implementation of miniflann is releasing the trained index, and
rebuilding the index from the beginning.
But, some indexing algorithms like the LSH are able to add the indexing
data after that.
This branch is implementation of that optimization for LshIndex
FlannBasedMatcher in the feature2d.

(cherry picked from commit 8910508b)

* cmake CMP0054 and CMP0045
* aarch64 build
* portable code options in PCH cmake
* some of gcc 4.9 warnings

- Use cv::AutoBuffer rather than new allocation
- Fix "assignment operator could not be generated" warning

- updated existing Doxyfile.in
- added corresponding cmake instructions
- added some specific files (layout, icon)
- clean existing doxygen warnings

Conflicts:
	CMakeLists.txt
	doc/CMakeLists.txt
	modules/core/include/opencv2/core.hpp
	modules/core/include/opencv2/core/base.hpp
	modules/core/include/opencv2/core/cuda.inl.hpp
	modules/core/include/opencv2/core/mat.hpp
	modules/core/include/opencv2/core/matx.hpp
	modules/core/include/opencv2/core/types.hpp
	modules/flann/include/opencv2/flann/lsh_table.h
	modules/imgproc/include/opencv2/imgproc.hpp

- updated existing Doxyfile.in
- added corresponding cmake instructions
- added some specific files (layout, icon)
- clean existing doxygen warnings

1. someMatrix.data -> someMatrix.prt()
2. someMatrix.data + someMatrix.step * lineIndex -> someMatrix.ptr( lineIndex )
3. (SomeType*) someMatrix.data -> someMatrix.ptr<SomeType>()
4. someMatrix.data -> !someMatrix.empty() ( or !someMatrix.data -> someMatrix.empty() ) in logical expressions

Revert "Avoid obtaining several identical dimensions between two LSH sub-vectors by choosing orthogonal sub-vectors."

This reverts commit e85bacff.

This reverts commit 8e93c19d.

Revert "Allows to choose orthogonal sub-vectors for LSH without using a static table among LshTable instances"

This reverts commit e63d7de8.

This reverts commit 2f8b5731.