Improve hyperbolic LCSs in ocean data-set demos

Commit ed77890209ea4c70b19548c8d6cabafb14fb2df3 changed the default
integration tolerance in seed_curves_from_lambda_max. The present
commit restores the tolerance used prior to commit
ed77890209ea4c70b19548c8d6cabafb14fb2df3 and improves the "smoothness"
of strainlines.