Actix Default Responder

Procedural macros for generating default actix_web::Responder implementation for a custom serialization.

Currently supported formats are:

1. JSON

2. Bincode

3. XML

Json Response

```rust

[derive(Serialize, PartialEq, JsonResponder)]

struct JsonResponse { name: String, } ```

XML Response

```rust

[derive(Debug, Serialize, PartialEq, XMLResponder)]

struct XMLResponse { name: String, } ```

Bincode Response

```rust

[derive(Debug, Serialize, PartialEq, BincodeResponder)]

struct BincodeResponse { name: String, } ```