title: React Native Navigator transition issue
body: <p>I have a simple RN app, when I call navigator.push({...}) to navigate to a different scene, the current scene slides out towards left, and the new scene slides in from right. The problem is the current scene slides much slower (seems it only moves about 1/4 of the screen width) than the new scene, so the new scene actually catches up and overlaps with the current scene before the current scene disappears.</p>
  
  <p>Any idea on how to fix this?</p>
  
  <p>RN version: 0.34
  Navigator (<strong>not</strong> NavigatorIOS)</p>
  
  <p>I am running the app in simulator.</p>
  
  <p>Thanks in advance.</p>