minor fix
minor fix

add color edge and some example of polyhedra

cnr-isti-vclab/meshlabjs,cignoni/meshlabjs,cnr-isti-vclab/meshlabjs,cnr-isti-vclab/meshlabjs,cignoni/meshlabjs,cignoni/meshlabjs,cnr-isti-vclab/meshlabjs,cignoni/meshlabjs,cnr-isti-vclab/meshlabjs,cignoni/meshlabjs