Support unmarshal nested interface type

[jinleiw]

I think it's better to support nested Interface, For example:

type Conf struct {
     IntVal int
     InterVal interface{}
}

type NestedStruct struct {
    Name string
    Age int
}
var config Conf

config.InterVal = &NestedStruct{}

decoder.decode(&config)

[pelletier]

Nested structs should be supported. Do you mind trying with name and age as public attributes (capitalized names)?

[jinleiw]

Sorry, spelling mistakes. Yes, they are public attributes:

type NestedStruct struct {
    Name string
    Age int
}

[jinleiw]

Could you help me review the commit “75121fd”, if ok, then I open up a pull request. Thanks