AVL Tree Map and Set in Rust

An ordered map and set implemented with an AVL tree (nearly balanced binary search tree) in Rust.

```rust use avl::AvlTreeMap;

let mut map = AvlTreeMap::new(); map.insert(0, "zero"); map.insert(1, "one"); map.insert(2, "two"); asserteq!(map.get(&1), Some(&"one")); map.remove(&1); assert!(map.get(&1).isnone());

use avl::AvlTreeSet;

let mut set = AvlTreeSet::new(); set.insert(0); set.insert(1); set.insert(2); asserteq!(set.get(&1), Some(&1)); set.remove(&1); assert!(set.get(&1).isnone()); ```

This is solely to get practice with the dark art of unsafe Rust. For all common purposes one of the standard library collections should be preferable.