Remove obsolete rustfmt options. (#222)
Remove obsolete rustfmt options. (#222)

Running `cargo fmt --all` gave lots of
```
Warning: Unknown configuration option `reorder_extern_crates`
Warning: Unknown configuration option `reorder_imported_names`
```
This PR removes these warnings.
googlecartographer/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer