Fixes ImageSampling.sample_patch to be restricted to the image dimensions.  Adds ManualPicker.change_rownames to handle mislabeled rows in batch. Adds cielab2000de difference metric to TestAlgorithms as well as handling of off image samples in template_based_finder by assigning (0,0,0).  Adds gen_utils.files_in_directory. Also begins several features for visualizing color categories in ColorCategorization.