implemented variation of information error measure
cleaned SegmentExtractor
replaced distance threshold for segment selection with overlap check
added program option to disable segmentation costs in objective
added maximal set difference as criteria for slice similarity in  StackSliceExtractor
removed Features' add() method in favour of resize() and get()
added program option to disable the slice distance feature
made overlap normalization a public method of feature Overlap
greatly improved performance of SegmentExtractor by reusing overlap results [...]

greatly improved performance of SegmentExtractor by reusing overlap results,
also added program options for individual overlap thresholds for branches and
continuations, and a program option for the size ratio threshold of branch
targets
updated imageprocessing
added ProblemConfiguration
added output "objective" and "problem configuration" to Sopnet
added costs to FeaturesView
added ProgramOptions for segmentation cost parameters
made ImageExtractor less verbose
added input "annotation" to NeuronsImageWriter to append the directory name with a number
extended GridSearch to segmentation cost parameters