feat(router): enforce convention of CamelCase names in route aliases

Closes #4083

modules/angular2/src/router/route_recognizer.ts

@@ -44,6 +44,12 @@ export class RouteRecognizer {
   config(config: RouteDefinition): boolean {
     var handler;
 
+    if (isPresent(config.as) && config.as[0].toUpperCase() != config.as[0]) {
+      var suggestedAlias = config.as[0].toUpperCase() + config.as.substring(1);
+      throw new BaseException(
+          `Route '${config.path}' with alias '${config.as}' does not begin with an uppercase letter. Route aliases should be CamelCase like '${suggestedAlias}'.`);
+    }
+
     if (config instanceof AuxRoute) {
       handler = new SyncRouteHandler(config.component, config.data);
       let path = config.path.startsWith('/') ? config.path.substring(1) : config.path;