title: Angular2: CoreModule vs SharedModule
body: <p>Could somebody explain what's a <code>SharedModule</code> and a <code>CoreModule</code> stand for?</p>
  
  <p>I've been watching several project out there are using this approach in order to build its angular projects.</p>
  
  <ol>
  <li>Why do I need two modules?</li>
  <li>When should I import each one?</li>
  <li>Which <code>imports</code>, <code>exports</code>, <code>declarations</code> should each one have?</li>
  </ol>