add "--brightness" and "--saturation" alias for hue CLI

I've added `--brightness` and `--saturation` options as aliases for `--bri` and `--sat`, because `Readme.markdown` using `--brightness`.

    $ hue light 2 --brightness 20
    $ hue light 3 --saturation 200

It works.

![image](https://cloud.githubusercontent.com/assets/34204/4098473/188acba8-3023-11e4-9c4a-fb97b294fde0.png)