title: Angular Material 2 DatePicker with only month and year
body: <p>I was looking for a way to make the angular material datepicker 2 change to only year and month mode but it does not have that option in the documentation</p>
  
  <p>I can set the startView but when month or year is selected, change to Day mode</p>
  
  <pre><code>&lt;md-form-field&gt;
       &lt;input mdInput [mdDatepicker]="picker" placeholder="Choose a date"&gt;
       &lt;md-datepicker-toggle mdSuffix [for]="picker"&gt;&lt;/md-datepicker-toggle&gt;
       &lt;md-datepicker #picker startView="year" [startAt]="startDate"&gt;&lt;/md-datepicker&gt;
  &lt;/md-form-field&gt;
  </code></pre>
  
  <p>I want this: <a href="https://plnkr.co/edit/eV2Kmt?p=preview" rel="nofollow noreferrer">https://plnkr.co/edit/eV2Kmt?p=preview</a></p>
  
  <p>But that plunker is in angular material 1</p>
  
  <p>Any help? :)</p>