title: Promise.all behavior with RxJS Observables?
body: <p>In Angular 1.x I would sometimes need to make multiple <code>http</code> requests and do something with all the responses. I would throw all the promises in an array and call <code>Promise.all(promises).then(function (results) {...})</code>.</p>
  
  <p>Angular 2 best practices seem to point towards the use of RxJS's <code>Observable</code> as a replacement to promises in <code>http</code> requests. If I have two or more different Observables created from http requests, is there an equivalent to <code>Promise.all()</code>?</p>