Added a curvature parameter to region_3d.h
Files used for organized multiplane segmentation have been modified to store the curvature of the regions (organized_multi_plane_segmentation.hpp) and to experiment with different variable thresholds for planar region growing (plane_coefficient_comparator.h).
Also, a bunch of commented code is left in 'organized_connected_component_segmentation.hpp' to experiment later with different strategies for region growing.