Rust port of libdivide

For the purpose of original libdivide, see libdivide.com.

This is port of libdivide 4.0 with scalars support.

Cargo crate name is libdivide

Example

```rust use libdivide::Divider;

let d = Divider(5); // this is slow let r = 100 / &d; // this is fast ```