WITH_WINRT -> ENABLE_WINRT_MODE;
Some temporary char* replaced with Ptr<char>;
Build fix for regular WIN32;
Windows Platform SDK and MSVC search added to cmake;
Warinig fixes.

Additional CMAKE flag WITH_WINRT added.

I've left HAVE_LIBPTHREAD as a CMake variable, since TBB's build depends on it.

Some macros in internal.hpp depended on HAVE_ALLOCA_H, but they were, in turn,
unused, so I've just deleted them all.

Issue #2868

Fixed flann build with NEON;
Fixed Haming distance with NEON;
Honest cvRound for WinRT added;
cvRound test added;
Video IO with direct show disabled;

TIFF build was fixed;
Direct Show back-end was enabled;
More accurate guards implemented.

GPU module turned off;
TIFF support turned off;
Windows Managment and Video IO (VFW) turned off.

This should be safe todo unless we are writing a signal handler.

The video(4) driver provides a Video4Linux2 compatible API for
various video peripherals. This patch propagates HAVE_VIDEOIO if
the sys/videoio.h include file is found, which is the signature of
video(4).

- added CMake toolchain file
- added WITH_NVCUVID flag

Sometimes information about dependencies causing disabling were loosed and it
was not possible to correctly display these dependencies in status report

ReadMe.txt for OpenCV Manager added;
share folder excluded from SDK.