Tiny RNG, a minimal random number generator

Examples:

```rust use tiny_rng::{Rng,Rand};

fn main() {
    let seed: u64 = 0;
    let mut rng = Rng::new(seed);

    // Throw a dice 10 times.
    let v: Vec<u32> = (0..10).map(|_| rng.rand_range_u32(1,6)).collect();
    println!("{:?}\n",v);

    // Shuffle the array [0,1,...,99].
    let mut v: Vec<u32> = (0..100).collect();
    rng.shuffle(&mut v);
    println!("{:?}\n",v);
}

```