refactor(router): rename "as" to "name" in RouteConfig

BREAKING CHANGE:

This is a rename to make routing concepts easier to understand.

Before:

```
@RouteConfig([
  { path: '/', component: MyCmp, as: 'Home' }
])
```

After:

```
@RouteConfig([
  { path: '/', component: MyCmp, name: 'Home' }
])
```

Closes #4622

Closes #4896

modules/angular2/examples/router/ts/reuse/reuse_example.ts

@@ -44,8 +44,8 @@ class MyCmp implements CanReuse,
   directives: [ROUTER_DIRECTIVES]
 })
 @RouteConfig([
-  {path: '/', component: MyCmp, as: 'HomeCmp'},
-  {path: '/:name', component: MyCmp, as: 'HomeCmp'}
+  {path: '/', component: MyCmp, name: 'HomeCmp'},
+  {path: '/:name', component: MyCmp, name: 'HomeCmp'}
 ])
 class AppCmp {
 }