If we have perfect matches (min_dist == 0.0), then strict comparison
fails. Making it non-strict results in treating perfect matches as
good.

It was merged by mistake.

This reverts commit ab6be9b7.

Test cases (accuracy and performance) are provided.

It's the same as the implicitly defined one, and it causes a -Wextra warning
(not initializing the base class in a copy constructor).

This has no bearing on compilation, but it makes them show up in IDEs.

receives the number of neighbors joined into each detected object

Also, removing explicit include path configuration,
since QT_USE_FILE takes care of that.

The bug is a buffer overrun when border type is reflect101.
It is found that gfft crashed with input of size 100x100 on Intel CPU.

We don't really need it, it makes the code longer, and it can lead to
inconsistent paths when OpenCV is itself inside a symlink.

changed line281 -> line220
Presentation:
because line 220 give the globle var mDetectorType,and in line 230 it will be compared with mDeteorType !!!  it will never be unequal ~
fix:
change mDetectorType(previous globle var) to a new local val tmpDetectorType

+ interpolateFrames and createOpticalFlowNeedleMap