Rust 1.29.2

# Raw Pointers

There is a new edition of the book and this is an old link.

> Raw pointers are allowed to ignore many of the rules that references have to follow.

    let mut num = 5;

    let r1 = &num as *const i32;
    let r2 = &mut num as *mut i32;Run

Here are the relevant sections in the new and old books:

- In the second edition: Ch 19.01 — Unsafe Rust, section Dereferencing a Raw Pointer
- In the first edition: Ch 3.35 — Raw Pointers