feature request: sort by a list of scaffold names

I would like to request a feature of sorting by a list of scaffold names. This could be passed as a file in this format:

```
sca1
sca10
sca20
extra_scaffold2
chromosome5
```

This would be useful, at least to me, for determining the sort order of scaffolds after mapping Hi-C data, but before generating the pretext file. Thank you for your consideration!