message: Made transparent only when fluently skipped
  Don't want a breaking change so keep the scene background opaque white for normal navigation
diff: @@ -104,12 +104,13 @@ class Scene extends React.Component<SceneProps, SceneState> {
  var {crumb, title, sceneKey, popped, navigationEvent: {stateNavigator}} = this.props;
  var {crumbs} = stateNavigator.stateContext;
  var {state, data} = navigationEvent ? navigationEvent.stateNavigator.stateContext : crumbs[crumb];
  + var backgroundColor = navigationEvent ? '#fff' : 'rgba(255,255,255, 0)';
  return (
  <NVScene
  sceneKey={sceneKey}
  {...this.getAnimation()}
  title={title(state, data)}
  - style={styles.scene}
  + style={[styles.scene, {backgroundColor}]}
  onWillAppear={this.onWillAppear}
  onPopped={() => popped(sceneKey)}>
  <BackButton onPress={this.handleBack} />
  @@ -125,7 +126,6 @@ var NVScene = requireNativeComponent<any>('NVScene', null);
  const styles = StyleSheet.create({
  scene: {
  - backgroundColor: 'rgba(255,255,255, 0)',
  position: 'absolute',
  top: 0, right: 0,
  bottom: 0, left: 0,
  