Translate a website (supporting URI schemes)

We are now supporting two URI schemes:
* `http(s)`
* `file`

### Translate a website

Open a browser session for viewing the translation (in Gooogle Translate):
```
$ trans :zh http://www.apple.com/iphone-6
```

You can also specify the browser to use:
```
$ trans :zh -browser=firefox http://www.apple.com/iphone-6
```

### Translate a file

```
$ trans :zh file://LICENSE
```