Please consider supporting struct-based documents

[finnbear]

Right now, this library supports interface-based documents of type map[string]interface{} and []interface{}. It would be useful to support any arbitrary struct-based or map[Stringer]anything-based document supported by encoding/json such as:

type Document struct {
    Foo Bar
}

type Bar struct {
    Number float64
}

With the pointer:
/Foo/Number