title: Angular Material DatePicker - Error: MdDatepicker: No provider found for DateAdapter
body: <p>Following Material docs, I:</p>
  
  <pre><code>import {MdDatepickerModule} from '@angular/material';
  </code></pre>
  
  <p>in root module and added it in providers list, but coudln't use it in template. Got this error:</p>
  
  <blockquote>
    <p>Uncaught (in promise): Error: MdDatepicker: No provider found for
    DateAdapter. You must import one of the following modules at your
    application root: MdNativeDateModule, or provide a custom
    implementation.</p>
  </blockquote>
  
  <p>So according to it, I removed last import and added:</p>
  
  <pre><code>import {MdNativeDateModule} from '@angular/material';
  </code></pre>
  
  <p>And now, looks like, it works. Why Material docs tells to import <code>MdDatepickerModule</code>, but not <code>MdNativeDateModule</code>? And how they differ?</p>