refactor(router): rename HTML5LocationStrategy to PathLocationStrategy

"HTML5" is a bit confusing. We want to differentiate between persisting location state
to the URL path, and the URL hash. Hence `PathLocationStrategy`.

BREAKING CHANGE

`HTML5LocationStrategy` -> `PathLocationStrategy`

Closes #3776

modules/angular2/src/router/path_location_strategy.ts

@@ -0,0 +1,32 @@
+import {DOM} from 'angular2/src/dom/dom_adapter';
+import {Injectable} from 'angular2/di';
+import {EventListener, History, Location} from 'angular2/src/facade/browser';
+import {LocationStrategy} from './location_strategy';
+
+@Injectable()
+export class PathLocationStrategy extends LocationStrategy {
+  private _location: Location;
+  private _history: History;
+  private _baseHref: string;
+
+  constructor() {
+    super();
+    this._location = DOM.getLocation();
+    this._history = DOM.getHistory();
+    this._baseHref = DOM.getBaseHref();
+  }
+
+  onPopState(fn: EventListener): void {
+    DOM.getGlobalEventTarget('window').addEventListener('popstate', fn, false);
+  }
+
+  getBaseHref(): string { return this._baseHref; }
+
+  path(): string { return this._location.pathname; }
+
+  pushState(state: any, title: string, url: string) { this._history.pushState(state, title, url); }
+
+  forward(): void { this._history.forward(); }
+
+  back(): void { this._history.back(); }
+}