Implements Bresenham's line drawing algorithm in Rust using an iterator over all points in the line. Most, if not all overhead should evaporate when inline by the compiler.
Example use:
```rust for (x, y) in Bresenham::new((0, 1), (6, 4)) { println!("{}, {}", x, y); }
```
Will print:
(0, 1)
(1, 1)
(2, 2)
(3, 2)
(4, 3)
(5, 3)