message: Simplified freeze container style
  Only need flex because scene already positioned absolute
diff: @@ -143,7 +143,7 @@ class Scene extends React.Component<SceneProps, SceneState> {
  <NavigationContext.Provider value={navigationEvent}>
  <Freeze freeze={freezable && crumbs.length !== crumb && navigationEvent
  && (!stateContext['peek'] || stateContext['peek'] !== this.props.navigationEvent)}>
  - <NVFreeze style={styles.scene}>
  + <NVFreeze style={styles.freeze}>
  {navigationEvent && this.props.renderScene(state, data)}
  </NVFreeze>
  </Freeze>
  @@ -163,6 +163,9 @@ const styles = StyleSheet.create({
  top: 0, right: 0,
  bottom: 0, left: 0,
  },
  + freeze: {
  + flex: 1
  + },
  });
  export default props => (
  