added saving of primitives as ply
added operator for sorting to Primitive.h and Efficient_ransac.h (reference and pointer versions)
replaced point on primitive for planes with one of the samples instead of using the CGAL function
added destructor to Octree.h for memory cleanup
sphere and cylinder primitive detection
connected component for planes and cylinders (non developable surfaces are more difficult)
several bugfixes (scoring of candidates, selection of samples