[Bug Report] plugin use 报错

### VUX version
2.9.1

### OS/Browsers version
mac chrome 66.0.3359.170

### Vue version
2.5.17-beta.0

### Code

```html
error in ./node_modules/vux/src/components/v-chart/v-tooltip.vue

Syntax Error:
38 | showItemMarker: this.showItemMarker,
39 | showValueInLegend: this.showValueInLegend,
> 40 | ...camelAttrs(this.options),
| ^
41 | ...camelAttrs(this.$attrs)
42 | }
43 | if (this.showXValue) {

Add @babel/plugin-proposal-object-rest-spread (https://git.io/vb4Ss) to the 'plugins' section of your Babel config to enable transformation.

{
"presets": [
"@vue/app",
["@babel/preset-env", {
"targets": {
"chrome": 52,
"browsers": ["last 2 versions", "safari 7"]
}
}]
],
"plugins": ["@babel/plugin-proposal-object-rest-spread"]
}

```

### Steps to reproduce
import { ToastPlugin } from 'vux'
Vue.use(ToastPlugin)

使用vue-cli 3.0

### What is Expected?
main.js
里面使用toast

### What is actually happening?
报错