feat: allow customize divider style via style props

[picodoth]

addressing #168

[coveralls]

Coverage remained the same at 99.676% when pulling 72e2558 on customize-divider-style into 1421abe on master.

[yesmeck]

propTypes

默认值最好改成 defaultProps

[yesmeck]

menu/src/Divider.jsx

Lines 5 to 13 in 87a72cd

	static propTypes = {
	className: PropTypes.string,
	rootPrefixCls: PropTypes.string,
	};
	static defaultProps = {
	// To fix keyboard UX.
	disabled: true,
	};

[picodoth]

@yesmeck disabled 还需要么？

[yesmeck]

有用的 7dfd303

[picodoth]

我也觉得有用，可是奇怪的是 divider 里都没引用这个 props

[picodoth]

这个地方我不敢乱改。。。照道理 直接
render() => { render (<li disabled>...</li>); }
不过 disabled attribute 在 li 上没定义啊