refactor(Location): out of router and into platform/common

closes https://github.com/angular/angular/issues/4943

BREAKING CHANGE:

`Location` and other related providers have been moved out of `router` and into `platform/common`. `BrowserPlatformLocation` is not meant to be used directly however advanced configurations may use it via the following import change.

Before:

```
import {
  PlatformLocation,
  Location,
  LocationStrategy,
  HashLocationStrategy,
  PathLocationStrategy,
  APP_BASE_HREF}
from 'angular2/router';

import {BrowserPlatformLocation} from 'angular2/src/router/location/browser_platform_location';
```

After:

```
import {
  PlatformLocation,
  Location,
  LocationStrategy,
  HashLocationStrategy,
  PathLocationStrategy,
  APP_BASE_HREF}
from 'angular2/platform/common';

import {BrowserPlatformLocation} from 'angular2/src/platform/browser/location/browser_platform_location';
```

Closes #7962

modules/angular2/src/web_workers/ui/platform_location.ts

@@ -1,4 +1,7 @@
-import {BrowserPlatformLocation} from 'angular2/src/router/location/browser_platform_location';
+import {
+  BrowserPlatformLocation
+} from 'angular2/src/platform/browser/location/browser_platform_location';
+import {UrlChangeListener} from 'angular2/platform/common';
 import {Injectable} from 'angular2/src/core/di';
 import {ROUTER_CHANNEL} from 'angular2/src/web_workers/shared/messaging_api';
 import {
@@ -10,7 +13,6 @@ import {bind} from './bind';
 import {LocationType} from 'angular2/src/web_workers/shared/serialized_types';
 import {MessageBus} from 'angular2/src/web_workers/shared/message_bus';
 import {EventEmitter, ObservableWrapper, PromiseWrapper} from 'angular2/src/facade/async';
-import {UrlChangeListener} from 'angular2/src/router/location/platform_location';
 
 @Injectable()
 export class MessageBasedPlatformLocation {

modules/angular2/src/web_workers/ui/router_providers.ts

@@ -1,6 +1,8 @@
 import {MessageBasedPlatformLocation} from './platform_location';
 import {CONST_EXPR} from 'angular2/src/facade/lang';
-import {BrowserPlatformLocation} from 'angular2/src/router/location/browser_platform_location';
+import {
+  BrowserPlatformLocation
+} from 'angular2/src/platform/browser/location/browser_platform_location';
 import {APP_INITIALIZER, Provider, Injector, NgZone} from 'angular2/core';
 
 export const WORKER_RENDER_ROUTER = CONST_EXPR([

modules/angular2/src/web_workers/worker/platform_location.ts

@@ -1,15 +1,11 @@
 import {Injectable} from 'angular2/src/core/di';
-import {
-  PlatformLocation,
-  UrlChangeEvent,
-  UrlChangeListener
-} from 'angular2/src/router/location/platform_location';
 import {
   FnArg,
   UiArguments,
   ClientMessageBroker,
   ClientMessageBrokerFactory
 } from 'angular2/src/web_workers/shared/client_message_broker';
+import {PlatformLocation, UrlChangeEvent, UrlChangeListener} from 'angular2/platform/common';
 import {ROUTER_CHANNEL} from 'angular2/src/web_workers/shared/messaging_api';
 import {LocationType} from 'angular2/src/web_workers/shared/serialized_types';
 import {PromiseWrapper, EventEmitter, ObservableWrapper} from 'angular2/src/facade/async';

modules/angular2/src/web_workers/worker/router_providers.ts

@@ -1,5 +1,5 @@
 import {ApplicationRef, Provider, NgZone, APP_INITIALIZER} from 'angular2/core';
-import {PlatformLocation} from 'angular2/src/router/location/platform_location';
+import {PlatformLocation} from 'angular2/platform/common';
 import {WebWorkerPlatformLocation} from './platform_location';
 import {ROUTER_PROVIDERS_COMMON} from 'angular2/src/router/router_providers_common';