fix(angular1_router): rename $route service to $rootRouter

The singleton service that represents the top level router was called
`$router` but this is confusing since there are actually lots of routers,
which depend upon where you are in the DOM. This is similar to the situation
with scopes.

This commit clarifies this singleton by renaming it to `$rootRouter`.

BREAKING CHANGE:

The `$router` injectable service has been renamed to `$rootRouter`

modules/angular1_router/src/module_template.js

@@ -4,7 +4,7 @@ angular.module('ngComponentRouter').
     // Because Angular 1 has no notion of a root component, we use an object with unique identity
     // to represent this. Can be overloaded with a component name
     value('$routerRootComponent', new Object()).
-    factory('$router', ['$q', '$location', '$$directiveIntrospector', '$browser', '$rootScope', '$injector', '$routerRootComponent', routerFactory]);
+    factory('$rootRouter', ['$q', '$location', '$$directiveIntrospector', '$browser', '$rootScope', '$injector', '$routerRootComponent', routerFactory]);
 
 function routerFactory($q, $location, $$directiveIntrospector, $browser, $rootScope, $injector, $routerRootComponent) {