Explore the ownership system in Rust

Updated for Rust 1.0. This guide is for a reader who knows basic syntax and building blocks of Rust but does not quite grasp how the ownership works. We will start very simple, and then will gradually increase complexity at a slow pace, exploring and discussing every new bit of detail. This guide will assume a very basic familiarity with let, fn, struct, trait and impl constructs. Our goal is to l