feat(router): add regex matchers

@petebacondarwin deserves credit for most of this commit.

This allows you to specify a regex and serializer function instead
of the path DSL in your route declaration.

```
@RouteConfig([
  { regex: '[a-z]+.[0-9]+',
    serializer: (params) => `{params.a}.params.b}`,
    component: MyComponent }
])
class Component {}
```

Closes #7325
Closes #7126

modules/angular2/router/router_link_dsl.ts

@@ -1,9 +1,9 @@
 import {TEMPLATE_TRANSFORMS} from 'angular2/compiler';
 import {Provider} from 'angular2/core';
-import {RouterLinkTransform} from 'angular2/src/router/router_link_transform';
+import {RouterLinkTransform} from 'angular2/src/router/directives/router_link_transform';
 import {CONST_EXPR} from 'angular2/src/facade/lang';
 
-export {RouterLinkTransform} from 'angular2/src/router/router_link_transform';
+export {RouterLinkTransform} from 'angular2/src/router/directives/router_link_transform';
 
 /**
  * Enables the router link DSL.