message: Updated nav native web readme to component api
diff: ```jsx
  import { StateNavigator } from 'navigation';
  import { NavigationHandler, NavigationContext } from 'navigation-react';
  -import { NavigationStack } from 'navigation-react-native';
  +import { NavigationStack, Scene } from 'navigation-react-native';
  const stateNavigator = new StateNavigator([
  { key: 'hello', route: '' },
  { key: 'world', trackCrumbTrail: true },
  ]);
  +if (Platform.OS === 'web') stateNavigator.start();
  +
  const Hello = () => {
  const { stateNavigator } = useContext(NavigationContext);
  return (
  - <TouchableHighlight
  + <Button
  + title="Hello"
  href={stateNavigator.historyManager.getHref(
  stateNavigator.navigate('world', { size: 20 })
  )}
  onPress={(e) => {
  e.preventDefault();
  stateNavigator.navigate('world', { size: 20 });
  - }}>
  - <Text>Hello</Text>
  - </TouchableHighlight>
  + }} />
  );
  };
  @@ -31,20 +32,13 @@ const World = () => {
  return <Text style={{ fontSize: data.size }}>World</Text>;
  };
  -const { hello, world } = stateNavigator.states;
  -
  -hello.renderScene = () => <Hello />;
  -world.renderScene = () => <World />;
  -
  -if (Platform.OS === 'web') stateNavigator.start();
  -else stateNavigator.navigate('hello');
  -
  const App = () => (
  <NavigationHandler stateNavigator={stateNavigator}>
  - <NavigationStack />
  + <NavigationStack>
  + <Scene stateKey="hello"><Hello /></Scene>
  + <Scene stateKey="world"><World /></Scene>
  + </NavigationStack>
  </NavigationHandler>
  );
  -
  -export default App;
  ```
  \ No newline at end of file
  