Initial Windows RT support commit.
GPU module turned off;
TIFF support turned off;
Windows Managment and Video IO (VFW) turned off.
Multiple Windows RT fixes

TIFF build was fixed;
Direct Show back-end was enabled;
More accurate guards implemented.
More accurate guards for WinRT features in CMake.
Highgui tests for GUI disabled for WinRT;
Warnings fix;
Multiple fixes for WinRT

Fixed flann build with NEON;
Fixed Haming distance with NEON;
Honest cvRound for WinRT added;
cvRound test added;
Video IO with direct show disabled;
use perf test replace performance sample
Video IO tests turned off for ARM WinRT.
HAVE_WIN32UI and HAVE_VFW checks and defines added.
Perf tests for Video IO on WInRT fixed.
fixed bug in TVL1 optical flow:

initial optical flow was not cleaned during the second call
In response to Bug #2927 

change to reject contours with moms.m00 = 0.0
Port dft.py sample from cv to cv2
Fix typo leading to heap corruption in OutputArray::create
Merge pull request #723 from virtuald:2.4
Merge pull request #721 from jet47:tvl1-bug-fix
contours with zero area rejected

reject contours with zero area by using the "continue" statement to be in sync with the condition checking style used in the whole file
fixed misprint in MatOp::augAssignXor
removed unnecessary tmp variable (convertTo can work in-place)
fixed misprint in icvCreateIsometricImage
fixed misprint in imgwarp.cpp