- prevented the PositionDependentMeasurementModel from learning if the target patch could not be extracted
- fixed bugs within GradientHistogramFilter
- extended the GradientHistogramFilter to deliver weights for two bins (next to the gradient) instead of only the lesser one
- removed the offset parameter from GradientHistogramFilter
- added a four-channel version to the histogram feature extractors
Merge branch 'refact' of github.com:elador/FeatureDetection into refact