title: Sending a post request in spray
body: <p>I need to make a simple HTTP request using <code>spray</code> framework. I found some examples on their web site but they turned out to be complicated and involving Akka which is not necessary for me. </p>
  
  <p>Besides, I need to be able to fill in a request's headers (like <code>X-Application</code>, <code>content-type</code>, etc) and, of course, a requests's post data (in my case, it would be a data in JSON).</p>
  
  <p>So how do I do that?</p>