Support wire action chaining?

Instead of:

```
w = Wires()
w.one_callable.wire(do_this)
w.one_callable.wire(do_that)
```

Wire action chaining could be supported:
```
w = Wires()
w.one_callable.wire(do_this).wire(do_that)
```

Notes:
* Trivial to implement.
* Not sure if readability improves or not.
* If implemented, unwire actions should also be chainable.