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
}
}
}
]
}
```
Wrapping each node with JSAPI class and passing parent to it is not
reliable. Parent may be changed but the reference will stay.
Here I wasn't able to detach comment from parent node for some reason.
Explicit parent node inferred while ast traverse is easier to debug and
work with. Eventually we will not need to wrap each node with JSAPI class.
Here we add [xast](https://github.com/syntax-tree/xast) support
to three basic nodes: doctype, instruction and comment
Some tests are rewritten instead of checking each field to `.include`
assertion which is able to match shape of object.
