Support deserializing structs from lists

[bryanburgers]

serde and serde_json have support for deserializing structs and
adjacently-tagged enums from sequences. I had no idea!

#[derive(serde::Deserialize)]
struct Person {
    name: String,
    age: u8,
}

let input = r#"["Arthur Dent", 42]"#;

let person: Person = serde_json::from_str(input).unwrap();
assert_eq!(person.name, "Arthur Dent");
assert_eq!(person.age, 42);

Fixes #87

[jlajoie]

Eww but also, neat? Had no clue 👍🏼