Add option to get result as an object, and not as a formatted text

Right now we are getting the result as text, something like this

```
command: npm run find:standard
code: 0
failed: false
killed: false
signal: null
timedOut: false

stdout:
-------
> nested@1.0.0 find:standard /Users/gleb/git/bin-up/test/nested
> $(../../bin/bin-up standard)
-------
stderr:
-------
Found /Users/gleb/git/bin-up/node_modules/.bin/standard
-------
```

it would be nice to sometimes get results from `execa-wrap` straight from execa