Remove commented feature properties

Signed-off-by: Rafael Ravedutti <rafaelravedutti@gmail.com>

examples/dem.py

@@ -145,10 +145,6 @@ psim.add_property('inv_inertia', pairs.matrix())
 psim.add_property('rotation_matrix', pairs.matrix())
 psim.add_property('rotation_quat', pairs.quaternion())
 psim.add_feature('type', ntypes)
-#psim.add_feature_property('type', 'stiffness_norm', pairs.real(), [stiffnessNorm for i in range(ntypes * ntypes)])
-#psim.add_feature_property('type', 'stiffness_tan', pairs.real(), [stiffnessTan for i in range(ntypes * ntypes)])
-#psim.add_feature_property('type', 'damping_norm', pairs.real(), [dampingNorm for i in range(ntypes * ntypes)])
-#psim.add_feature_property('type', 'damping_tan', pairs.real(), [dampingTan for i in range(ntypes * ntypes)])
 psim.add_feature_property('type', 'friction_static', pairs.real(), [frictionStatic for i in range(ntypes * ntypes)])
 psim.add_feature_property('type', 'friction_dynamic', pairs.real(), [frictionDynamic for i in range(ntypes * ntypes)])
 psim.add_contact_property('is_sticking', pairs.int32(), 0)