fix(TranslateService): Use the injector to instantiate HTTP_PROVIDERS

Fixes #17
Fixes #13

Author: ocombe

src/translate.service.ts

@@ -1,5 +1,5 @@
-import {Injectable, EventEmitter} from 'angular2/core';
-import {Http, Response} from 'angular2/http';
+import {Injectable, EventEmitter, Injector} from 'angular2/core';
+import {Http, Response, HTTP_PROVIDERS} from 'angular2/http';
 import {Observable} from 'rxjs/Observable'
 import 'rxjs/add/observable/fromArray.js';
 import 'rxjs/add/operator/share.js';
@@ -68,8 +68,13 @@ export class TranslateService {
     private defaultLang: string = 'en';
     private langs: Array<string>;
     private parser: Parser = new Parser();
+    private http: Http;
 
-    constructor(private http: Http) {
+    constructor() {
+        // We make sure that HTTP_PROVIDERS has been created & instantiated
+        // because sometimes it hasn't been provided in bootstrap
+        var injector = Injector.resolveAndCreate([HTTP_PROVIDERS]);
+        this.http = injector.get(Http);
         this.useStaticFilesLoader();
     }