added VLC

I would've thought it to be relatively straight-forward to add an application, but this is erroring out for me. Anybody know why?

```
Traceback (most recent call last):
  File "/usr/local/bin/mackup", line 26, in <module>
    mackup.main.main()
  File "/usr/local/Cellar/mackup/0.7.3/lib/python2.7/site-packages/mackup/main.py", line 47, in main
    app = ApplicationProfile(mckp, app_db.get_files(app_name))
  File "/usr/local/Cellar/mackup/0.7.3/lib/python2.7/site-packages/mackup/appsdb.py", line 106, in get_files
    return self.apps[name]['configuration_files']
KeyError: 'vlc'
```

If it's something I can fix, I'll gladly do so before this is merged.