Openni2 support
Merge remote-tracking branch 'origin/master' into Openni2Support

Conflicts:
	modules/highgui/CMakeLists.txt
	modules/highgui/include/opencv2/highgui.hpp
	modules/highgui/include/opencv2/highgui/highgui_c.h
Openni2 support
Add depends from highgui to imgcodecs and videoio. And include header from imgcodecs and videoio to imgcodecs
Fixed ippiDFT call
Merge pull request #2995 from ElenaGvozdeva:ipp_DFT
Merge pull request #2919 from larshg:Openni2Support
Merge pull request #2990 from vbystricky:highgui_split2
Added accuracy and performance tests for DFT all modes.
Merge pull request #3000 from akarsakov:ocl_dft_new_tests
Merge branch 'master' of https://github.com/Itseez/opencv.git