title: REST standard for checking if resource exists
body: <p>What is the REST way to check if resource exists or not? 
  Let say you have some resource called Project.
  By my understating one of this would be the way :</p>
  
  <p>GET the resource</p>
  
  <pre><code>GET /rest/projects/123
  
  GET /rest/projects/someCriteria
  
  GET /rest/projects/listOfIds
  </code></pre>
  
  <p>simple but this way the entire object is retrieved if available and we just want to check if it is there.
  Is there more elegant solution, maybe using HEAD? </p>