Ensure that two types are the same, or fail with a compilation error.

``` use sametypes::assertsame_types;

assertsametypes!(u32, u32, u32, u32); ```

```compilefail use sametypes::assertsametypes;

// Fails with the message: // the trait SameTypes is not implemented for (i32, u32) assertsametypes!(u32, u32, i32, u32); ```