title: Animation doesn't show steps-in-between
body: <p>I have created a simple function that would "animate" the cell backcolor at a tap, it works perfectly fine:</p>
  
  <pre><code>        Color nOldColor = _grid.BackgroundColor;
  
          for (int i = 0; i &lt;= 100; i += 5)
          {
              double f = (double)i / (double)100;
              Color nNewColor = PCLHelper.BlendColors(nOldColor, Color.Red, f);
              _grid.BackgroundColor = nNewColor;
              _label1.BackgroundColor = nNewColor;
              await Task.Delay(5);
          }
          _grid.BackgroundColor = nOldColor;
          _label1.BackgroundColor = nOldColor;
  </code></pre>
  
  <p>Now I wanted to do the same with an Animation, but the animation doesn't show the steps "in-between" but rather (as it looks to me) switches to the final color:</p>
  
  <pre><code>    private async void animateButtonTouched()
      {
  
          int repeatCountMax = 100;
          Color nOldColor = _grid.BackgroundColor;
  
          var repeatCount = 0;
          _grid.Animate("changeBG", new Animation((val) =&gt;
          {
              double f = (double)repeatCount / (double)100;
              Color nNewColor = PCLHelper.BlendColors(nOldColor, Color.Red, f);
              _grid.BackgroundColor = nNewColor;
              _label1.BackgroundColor = nNewColor;
          }),
          5, //duration. I've also tried it with 100. Nothing helped
          finished: (val, b) =&gt;
          {
              repeatCount++;
          }, repeat: () =&gt;
          {
              return repeatCount &lt; repeatCountMax;
          });
  </code></pre>
  
  <p>What am I doing wrong?</p>