Option to skip iso-traverse

Many integrations already do their own isodate formatting, so it would be nice to be able to opt-out of it at the root level. This helps performance for large events a good bit.

```
                      Facade - (default)
          94,584 op/s » new Facade()

                      Facade - traverse:false
       1,802,782 op/s » new Facade()
```