Angular4's HttpClient for node.js

Just install the package in your project and if you use
injection-js, import HTTP_CLIENT_PROVIDERS and add
them to your injector's providers.

If you want to use the HttpClient without using injection-js
in your own project, importing and running createHttpClient()
will create and resolve the HttpClient for you, giving you an
instance of it to use directly. It takes an _options_ object within
which the interceptors key is an array of HttpInterceptors.

Note: HttpClient taken from Angular 5.0.0-beta.5,
and made to work independently of Angular.

$3

#### 1. injection-js

``typescript
@Injectable()
class TestInterceptor implements HttpInterceptor {
intercept(request: HttpRequest, next: HttpHandler): Observable> {
console.warn('intercepted');
return next.handle(request);
}
}

@Injectable()
class GoogleTest {
constructor(private httpClient: HttpClient) {}

run() {
this.httpClient.get('http://www.google.com', {responseType: 'text'}).subscribe(
res => console.dir(res)
);
}
}

const injector = ReflectiveInjector.resolveAndCreate([
...HTTP_CLIENT_PROVIDERS,
{ provide: HTTP_INTERCEPTORS, useClass: TestInterceptor, multi: true },
GoogleTest
]);

const googleTest = injector.get(GoogleTest);

googleTest.run();
`

#### 2. Non-IoC usage

`typescript
class TestInterceptor implements HttpInterceptor {
intercept(request: HttpRequest, next: HttpHandler): Observable> {
console.warn('intercepted');
return next.handle(request);
}
}

const httpClient: HttpClient = createHttpClient({interceptors: [TestInterceptor]});
httpClient.get('http://www.google.com', {responseType: 'text'}).subscribe(
res => console.dir(res)
);
``