refactor(router): improve recognition and generation pipeline

This is a big change. @matsko also deserves much of the credit for the implementation.

Previously, `ComponentInstruction`s held all the state for async components.
Now, we introduce several subclasses for `Instruction` to describe each type of navigation.

BREAKING CHANGE:

Redirects now use the Link DSL syntax. Before:

```
@RouteConfig([
	{ path: '/foo', redirectTo: '/bar' },
	{ path: '/bar', component: BarCmp }
])
```

After:

```
@RouteConfig([
	{ path: '/foo', redirectTo: ['Bar'] },
	{ path: '/bar', component: BarCmp, name: 'Bar' }
])
```

BREAKING CHANGE:

This also introduces `useAsDefault` in the RouteConfig, which makes cases like lazy-loading
and encapsulating large routes with sub-routes easier.

Previously, you could use `redirectTo` like this to expand a URL like `/tab` to `/tab/posts`:

@RouteConfig([
	{ path: '/tab', redirectTo: '/tab/users' }
	{ path: '/tab', component: TabsCmp, name: 'Tab' }
])
AppCmp { ... }

Now the recommended way to handle this is case is to use `useAsDefault` like so:

```
@RouteConfig([
	{ path: '/tab', component: TabsCmp, name: 'Tab' }
])
AppCmp { ... }

@RouteConfig([
	{ path: '/posts', component: PostsCmp, useAsDefault: true, name: 'Posts' },
	{ path: '/users', component: UsersCmp, name: 'Users' }
])
TabsCmp { ... }
```

In the above example, you can write just `['/Tab']` and the route `Users` is automatically selected as a child route.

Closes #4728
Closes #4228
Closes #4170
Closes #4490
Closes #4694
Closes #5200

Closes #5475

modules/angular1_router/src/module_template.js

@@ -9,7 +9,11 @@ function routerFactory($q, $location, $$directiveIntrospector, $browser, $rootSc
   // the contents of `../lib/facades.es5`.
   //{{FACADES}}
 
-  var exports = {Injectable: function () {}};
+  var exports = {
+    Injectable: function () {},
+    OpaqueToken: function () {},
+    Inject: function () {}
+  };
   var require = function () {return exports;};
 
   // When this file is processed, the line below is replaced with
@@ -31,12 +35,19 @@ function routerFactory($q, $location, $$directiveIntrospector, $browser, $rootSc
   // property in a route config
   exports.assertComponentExists = function () {};
 
-  angular.stringifyInstruction = exports.stringifyInstruction;
+  angular.stringifyInstruction = function (instruction) {
+    return instruction.toRootUrl();
+  };
 
   var RouteRegistry = exports.RouteRegistry;
   var RootRouter = exports.RootRouter;
 
-  var registry = new RouteRegistry();
+
+  // Because Angular 1 has no notion of a root component, we use an object with unique identity
+  // to represent this.
+  var ROOT_COMPONENT_OBJECT = new Object();
+
+  var registry = new RouteRegistry(ROOT_COMPONENT_OBJECT);
   var location = new Location();
 
   $$directiveIntrospector(function (name, factory) {
@@ -47,10 +58,6 @@ function routerFactory($q, $location, $$directiveIntrospector, $browser, $rootSc
     }
   });
 
-  // Because Angular 1 has no notion of a root component, we use an object with unique identity
-  // to represent this.
-  var ROOT_COMPONENT_OBJECT = new Object();
-
   var router = new RootRouter(registry, location, ROOT_COMPONENT_OBJECT);
   $rootScope.$watch(function () { return $location.path(); }, function (path) {
     if (router.lastNavigationAttempt !== path) {