Personal config overrides (part of) default

I set a custom prompt in my `~/.altsql.yml` as follows:

```

---
prompt: 'foo > '
```

No other entries. 

The output with this configuration is ASCII only.

Looks like I need to add:

```
view_plugins: 
    - Color
    - UnicodeBox
```

In order for proper color and unicode output.  Looks like the default is being overriden.
