title: setAttribute for animation component 'to' attribute using position fails to set
body: <p>I'm using A-Frame (webVR) to make a multi panorama explorer. The world has a few 3d buttons (with panorama mapped spheres at each button position). You click on a button, and an animation component moves the camera from its current location to the button location. A custom component containing a listener (for click events on buttons), uses setAttribute to set the 'to' and 'from' attributes of an animation component on the camera. An emit command triggers the animation. Unfortunately it fails, and I can see that the 'from' attribute is not setting correctly (it is setting to the same as 'to'). It doesn't throw errors, but I can see in the console that the from will not set,even though I set it explicitly.</p>
  
  <p>I've already got this working in a previous version. You can see and test it here:
  <a href="https://glitch.com/~camera-jumper" rel="nofollow noreferrer">https://glitch.com/~camera-jumper</a></p>
  
  <p>In this version, I don't set the from attribute, and it still works fine, presumably because it takes the previous value as a default.</p>
  
  <p>Then I built in some other functionality and now it is failing. You can see the current version here:
  <a href="https://glitch.com/~panojumper" rel="nofollow noreferrer">https://glitch.com/~panojumper</a></p>
  
  <pre><code>AFRAME.registerComponent('buttoncontrol', { 
      schema: {
          pano:{type:'string',default: 'pSphere1'} 
      },  
      init: function(){   
          var el = this.el;       
          var cam = document.querySelector('#camera'); 
          var panoManEntity = document.querySelector('#panoMan'); 
          var panoName = this.data.pano;
          console.log(cam.getAttribute('animation__jump', 'to'));
          this.el.addEventListener('click', function(evt){
  
              // Animate the camera moving to the button position
              var btnpos = el.getAttribute('position'); 
              var cam = document.querySelector('#camera');
              var campos = cam.getAttribute('position');              
  
              cam.setAttribute('animation__jump','to', {x: btnpos.x, y: 
                btnpos.y, z: btnpos.z });             
              cam.setAttribute('animation__jump','from', {x: campos.x, y: 
                campos.y, z: campos.z });     
              cam.emit('camjump');
          }); 
      }
  });
  </code></pre>
  
  <p>I expect setAttribute for 'from' to be what I am setting it to, but it is the same as the 'to' value.</p>