fallback to default node settings; selected node and seed node styles

package-lock.json

package.json

...app/components/network-legend/network-legend.component.ts

src/app/config.ts

src/app/interfaces.ts

src/app/network-settings.ts

src/app/pages/explorer-page/explorer-page.component.ts

...app/services/netex-controller/netex-controller.service.ts

src/index.html