message: added placeholder prop fro ios picker
diff: @@ -84,7 +84,7 @@ class PickerNB extends Component {
  renderButton() {
  const onPress = () => { this._setModalVisible(true); };
  - const text = this.state.currentLabel ? this.state.currentLabel : this.props.defaultLabel;
  + const text = this.state.currentLabel ? this.state.currentLabel : this.props.placeholder;
  if (this.props.renderButton) {
  return this.props.renderButton(onPress, text, this);
  }
  @@ -95,7 +95,11 @@ class PickerNB extends Component {
  transparent
  onPress={onPress}
  >
  - <Text note={(this.props.note)} style={this.props.textStyle}>{text}</Text>
  + {(this.state.currentLabel) ?
  + <Text style={this.props.textStyle} note={(this.props.note)}>{this.state.currentLabel}</Text>
  + :
  + <Text style={this.props.textStyle} note>{this.props.placeholder}</Text>
  + }
  {(this.props.iosIcon === undefined) ? null : this.renderIcon()}
  </Button>;
  }
  