aglio ... -o out/index.html doesn't create a folder

Hello,

Is it possible to tell aglio to create a folder with the "-o" option ?

For example, if I run aglio like this:

``` bash
aglio -i doc.apib -o out/index.html
```

I will have this error if the folder `out` doesn't exist:

``` bash
>> { Error: ENOENT: no such file or directory, open 'out/index.html'
at Error (native)
errno: -2,
code: 'ENOENT',
syscall: 'open',
path: 'out/index.html' }
```

I know it's because aglio only check if it can create the file instead of creating the folder if he can't.

Can you do something for that ?