I saw complaints about `extendDefaultPlugins` api
- it cannot be used when svgo is installed globally
- it requires svgo to be installed when using svgo-loader or svgo-jsx
- it prevents using serializable config formats like json
In this diff I introduced the new plugin which is a bundle of all
default plugins.
```js
module.exports = {
plugins: [
'preset_default',
// or
{
name: 'preset_default',
floatPrecision: 4,
overrides: {
convertPathData: {
applyTransforms: false
}
}
}
]
}
```
Ref https://github.com/syntax-tree/xast
- added type: root | element
- renamed elem to name
- replaced "elem" property checks with check for correct type
