ipset 0.1.0

A wrapper for libipset
Documentation
## IPSet

A library wrapper for `libipset`.  
Support the following commands:

* add
* del
* test
* create
* list
* destroy
* flush

Support the following type:

* hash:ip
* hash:net not fully supported

### Example

  ```rust
  use ipset::{Session, SetType};

fn main() {
    let mut session = Session::new();
    if let Err(err) = session.create("test", SetType::HashIp, |builder| {
        builder.with_ipv6(false)?.build()
    }) {
        println!("create ipset failed:{:?}", err);
        return;
    }

    if let Err(err) = session.add("test", "127.0.0.1".parse().unwrap()) {
        println!("add ip to ipset failed:{:?}", err);
        return;
    }

    if let Err(err) = session.list("test") {
        println!("list ip from ipset failed:{:?}", err);
        return;
    }

    if let Err(err) = session.del("test", "127.0.0.1".parse().unwrap()) {
        println!("delete ip from ipset failed:{:?}", err);
        return;
    }

    if let Err(err) = session.flush("test") {
        println!("flush ipset failed:{:?}", err);
    }

    if let Err(err) = session.destroy("test") {
        println!("destroy ipset failed:{:?}", err);
    }
}
```