Add Replace With Animation feature to Navigator

src/Navigator.js

@@ -1186,6 +1186,33 @@ var Navigator = React.createClass({
       cb && cb();
     });
   },
+
+   /**
+    * Replace the previous scene with transition Animations.
+    * @param {object} route Route that replaces the previous scene.
+    */
+   replaceWithAnimation: function (route) {
+     const currentLength = this.state.presentedIndex + 1;
+     const currentRouteStack = this.state.routeStack.slice(0, currentLength);
+     const animationConfigFromSceneConfigStack = this.state.sceneConfigStack.slice(0, currentLength);
+     const nextStack = currentRouteStack.concat([route]);
+     const destIndex = nextStack.length - 1;
+     const nextSceneConfig = this.props.configureScene(route, nextStack);
+     const nextAnimationConfigStack = animationConfigFromSceneConfigStack.concat([nextSceneConfig]);
+
+     const newStack = currentRouteStack.slice(0, currentLength - 1).concat([route]);
+     this._emitWillFocus(nextStack[destIndex]);
+     this.setState({
+       routeStack: nextStack,
+       sceneConfigStack: nextAnimationConfigStack,
+     },() => {
+       this._enableScene(destIndex);
+       this._transitionTo(destIndex, nextSceneConfig.defaultTransitionVelocity, null, () => {
+         // Immediately reset the route stack after the transition is completed
+         this.immediatelyResetRouteStack(newStack);
+       });
+     });
+   },
 
   /**
    * Replace the current scene with a new route.