removed contrib, legacy and softcsscade modules; removed latentsvm and datamatrix detector from objdetect. removed haartraining and sft apps.
some of the stuff will be moved to opencv_contrib module.
in order to make this PR pass buildbot, please, comment off opencv_legacy, opencv_contrib and opencv_softcascade test runs.

Fixed compilation errors: removed using namespace from hpp file. This led to pulling cv::ACCESS_MASK to global namespace where conflict with the same name in 'windows.h'

Conflicts:
	apps/traincascade/boost.cpp

Made all STL usages explicit to be able automatically find all usages of
particular class or function.

(cherry picked from commit 2a6fb286)
(only cherry picked "apps/trancascade")

Fixed compilation errors: removed using namespace from hpp file. This led to pulling cv::ACCESS_MASK to global namespace where conflict with the same name in 'windows.h'

Allow to build samples via OpenCV binaries from distribution package
(find_package with OpenCV_DIR).

Conflicts:
	modules/core/include/opencv2/core/cuda.hpp
	modules/cudacodec/src/thread.cpp
	modules/cudacodec/src/thread.hpp
	modules/superres/perf/perf_superres.cpp
	modules/superres/src/btv_l1_cuda.cpp
	modules/superres/src/optical_flow.cpp
	modules/videostab/src/global_motion.cpp
	modules/videostab/src/inpainting.cpp
	samples/cpp/stitching_detailed.cpp
	samples/cpp/videostab.cpp
	samples/gpu/stereo_multi.cpp

This should allow many algorithms to take advantage of more parallelization
technologies.

This also fixes few clang build errors

e.g. <opencv2/core/core.hpp> become <opencv2/core.hpp>

Also renamed <opencv2/core/opengl_interop.hpp> to <opencv2/core/opengl.hpp>

Made all STL usages explicit to be able automatically find all usages of
particular class or function.