Renders a slice of integers (or anythign lese that supports the LowerHex or UpperHex traits as hex. For example, this:
```rust extern crate hexslice; use hexslice::AsHex;
fn main() { let foo = vec![0u32, 1 ,2 ,3]; println!("{:x}", foo.as_hex()); } ```
Displays: [0 1 2 3] on standard output (available with cargo run --example trivial).