Added OpenVX based processing to FAST (#7720)

* added wrapper for OVX FAST & fixes to IVX wrappers

* fixed type checks in wrappers, array downloading code simplified

* rewritten for new macro use

OpenVX pyrDown wrappers (#7793)

* wrappers for vx_pyramid added

* initial version of pyrDown() wrapper added

* disabled for Khronos

* rewritten for new macro use; border mode added to node

OpenVX optical flow PyrLK wrappers added (#7774)

* wrappers for vx_pyramid added

* initial version of Optical Flow PyrLK wrappers added

* array downloading code simplified

* disabled due to bad accuracy; fixed bugs, e.g. vendor-specific ones

* rewritten for new macro use

Build with ICC

Original commit is a5f19f7dd6ae5bc93f73e0417a9e0bfd34c01672

* GSoC 2016 - Adding toggle files to be used by tutorials.

Add a toggle option for tutorials.
* adds a button on the HTML tutorial pages to switch between blocks
* the default option is for languages: one can write a block
for C++ and another one for Python without re-writing the tutorial

Add aliases to the doxyfile.
* adding alises to make a link to previous and next tutorial.
* adding alias to specify the toggle options in the tutorials index.
* adding alias to add a youtube video directly from link.

Add a sample tutorial (mat_mask_opertaions) using the developed aliases:
* youtube alias
* previous and next tutorial alias
* buttons
* languages info for tutorial table of content
* code referances with snippets (and associated sample code files)

* Removing the automatic ordering.
Adding specific toggles for cpp, java and python.
Move all the code to the footer / header and Doxyfile.
Updating documentation.

The old behaviour is available via waitKeyEx() call or
via setting of OPENCV_LEGACY_WAITKEY environment variable

Added new overloaded functions for Mat and UMat that accepts std::vector<int> instead of int * for the sizes on a N-dimensional array.

This allows for an N-dimensional array to be setup in one line instead of two when using C++11 initializer lists. cv::Mat(3, {zDim, yDim, xDim}, ...) can be used instead of having to create an int pointer to hold the size array.

Documentation fixes for latest doxygen

This is based on testing OpenCV 3.1 with VisionWorks, which identified issues.
The tutorial now specifies 3 cherry-pick commands for opencv.