it takes a video file as input and shows colored optical flow.
Signed-off-by: Li Peng <peng.li@intel.com>

See https://github.com/opencv/opencv_contrib/issues/1048

tldDetector.cpp:465:22: warning: declaration shadows a field of 'cv::tld::TLDDetector' [-Wshadow]

fixed typo in comment (#1066)

Line 139: Fixed typo of word "length".

- made some of dependencies explicit
- removed dependencies to highgui and some other modules where possible
- modified some samples to build without modules

This patch adds ocl kernels to accelerate Dense Inverse Search
based optical flow algorithm, it acclerates 3 parts in the algorithm,
including 1) Structure tensor elements compute, 2) Patch inverse search,
3) Densification compute.

Perf and accuracy test are also added. The perf test shows it is 30%
faster than the current implementation.
Signed-off-by: Li Peng <peng.li@intel.com>

* added BackgroundSubtractorCNT

* doc fixes

* fixed typo