Soni's Serde Utilities

This crate provides some utilities for use with serde.

Currently, it provides MayBe<T>, an Option<T>-like that doesn't error if something is present but doesn't match a T. For example, it enables the JSON:

json { "bar": [] }

to successfully deserialize into the Rust struct:

```rust

[derive(Deserialize)]

struct Foo { bar: MayBe, } ```

as a foo.bar.is_none().