Angular2: CoreModule vs SharedModule : <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>
