vec4

vector 4 functions

```rust extern crate vec4;

fn main() { let a = [1, 1, 1, 1]; let b = [1, 1, 1, 1]; let mut out = vec4::new(0, 0, 0, 0);

vec4::add(&mut out, &a, &b);

assert_eq!(out, [2, 2, 2, 2]);

} ```