Adding class for BOW image matcher (Feature #3005).
Same prototype as BOWImgDescriptorExtractor, but do only the matching.
If the feature is accepted, the BOWImgDescriptorExtractor and BOWImgDescriptorMatcher should probably refactor with inheritance.
Add a class to compute the keypoints, descriptors and matching from an image should be added to.
Adding an export for HOGDetector compatibility.
An SVM train with HOG could export a single vector for HOGDetector.
Fix warning on precision lost due to double to float conversion.
Update PR after mdim review.
adding sample to train HOG and compare it with default people detector.
Update sample and code with external computation of HOG detector.
Fix compilation issues.
Applied fix mentioned in bugreport 3370. Seems to solve the issue.
Fix some warning.
Adding missing credit for a function.
Merge remote-tracking branch 'upstream/master' into svm_hog
Merge remote-tracking branch 'upstream/master' into bow_desc

Conflicts:
	modules/features2d/src/bagofwords.cpp
Remove duplicate functions.
Fix warnings as errors.
Fix useless space...
Fix name of parameter to have proper documentation.
Suppress a space!
Fix name of one parameter to fit the documentation.
Fix compilation issue related to previous commit.
fixed comparison to stop integer wrap around
Fix the documentation names.