Added nonrootwebbrowser to the list of files installed by setup.py

When installing WiFiz from Git, then running it, Python complains about not being able to find the `nonrootwebbrowser` module:

```
Traceback (most recent call last):
  File "/usr/share/wifiz/main.py", line 21, in <module>
    from nonrootwebbrowser import OpenReportWindow
ImportError: No module named nonrootwebbrowser
```

This PR fixes this by adding the file to the `setup.py` script.