include additional handlers for messages and conditions

Should be able to do something like:

_suppress messages_

which ivokes a `"muffleMessages"` restart

```r
suppress_messages(expr, classes = "message", package = NULL)
```

or print/`cat()` to a separate output:

```r
redirect_print(expr, file = connection)
```

Currently `messages` are sent to the `stderr()` but we could send them to different -- or multiple -- outputs
