Parameters for option feature

[yanganto]

The critical behavior in option feature is about applying a patch on a None.

Now we use .into(), and let the user implement the From trait as the default behavior.
This is the reason the option featuredependence on From`.

It is nice to have some optional parameters for option to handle the other two possible use cases.

• when applying a patch on none, the result will be none, such that the option feature will have no dependency
• when applying a path on none, the result will be a patched default instance, so the option feature will not be dependent on From but from Default

ref:
#31 (comment)
#31 (comment)