title: xamarin.forms.labs ImageButton issue
body: <p>I am using <strong>Xamarin.Forms</strong> and a <strong>Monodroid</strong> project. </p>
  
  <p>I use <strong>Xamarin.Forms.Labs</strong> to render an <strong>ImageButton</strong> control.</p>
  
  <p>Everytime I try to render the control in xaml I get this exception: </p>
  
  <blockquote>
    <p>System.TypeInitializationException: An exception was thrown by the
    type initializer for Xamarin.Forms.Labs.Controls.ImageButton --->
    System.MissingMethodException: Method 'BindableProperty.Create' was
    not found.</p>
  </blockquote>
  
  <p>Here is the main code of my page: </p>
  
  <pre><code>    &lt;ContentPage 
      xmlns="http://xamarin.com/schemas/2014/forms" 
      xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
      x:Class="*.MainPage"
      xmlns:controls="clr-namespace:Xamarin.Forms.Labs.Controls;assembly=Xamarin.Forms.Labs"&gt;
  &lt;ContentPage.Content&gt;
      &lt;controls:ImageButton HeightRequest="75" WidthRequest="175" ImageHeightRequest="50" ImageWidthRequest="50"  /&gt;
  
      &lt;/ContentPage.Content&gt;
  </code></pre>
  
  <p>I intentionally removed the attributes to see if they were the reason of this exception.</p>