Dust - data driven tests in Rust

For example: ```rust

![feature(plugin, decl_macro)]

![plugin(dust)]

[theory]

[data(1,1)]

[data(2,2)]

[data(3,3)]

[data(4,4)]

fn test_integer(a: i32, b: i32) { assert!(a==b); }

[theory]

[data("test", "test")]

[data("test2", "test2")]

fn test_str(a: &str, b: &str) { assert!(a==b); }

[test]

fn bla() { assert!(1==1); } ```