Fix typo: 'right direction' to 'y direction' in harris corner detector tutorial.

detector/descriptor.

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

sample code : https://github.com/Itseez/opencv/blob/master/samples/cpp/tutorial_code/features2D/SURF_descriptor.cpp

Bug #2888

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

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

Tutorial text was not consistent with tutorial source code in samples directory.
Inline source code was replaced on "includeliteral" directive with link to cpp file.