title: Missing XML resource type for PercentRelativeLayout Percentage value?
body: <p>It seems that the new Percent Support Library was released without allowing to reference a Percentage value in a dimension xml file.</p>
  
  <p>That is, instead of : </p>
  
  <pre><code> &lt;android.support.percent.PercentRelativeLayout
           xmlns:android="http://schemas.android.com/apk/res/android"
           xmlns:app="http://schemas.android.com/apk/res-auto"
           android:layout_width="match_parent"
           android:layout_height="match_parent"/&gt;
       &lt;ImageView
           app:layout_widthPercent="50%"
           app:layout_heightPercent="50%"
           app:layout_marginTopPercent="25%"
           app:layout_marginLeftPercent="25%"/&gt;
   &lt;/android.support.percent.PercentFrameLayout/&gt;
  </code></pre>
  
  <p>being able to code something like that :</p>
  
  <pre><code> &lt;android.support.percent.PercentRelativeLayout
       xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:app="http://schemas.android.com/apk/res-auto"
       android:layout_width="match_parent"
       android:layout_height="match_parent"/&gt;
   &lt;ImageView
       app:layout_widthPercent="@percent/myWidthPercent"
       app:layout_heightPercent="@percent/my/HeightPercent"
       app:layout_marginTopPercent="@percent/myMarginTophPercent"
       app:layout_marginLeftPercent="@percent/myMarginLeftPercent"/&gt;
  </code></pre>
  
  <p></p>
  
  <p>where myWidthPercent is defined in a resource files.</p>
  
  <p>Am i wrong (did i miss it with another name) or is it a feature request that we could send to google?</p>