Allow records to be exported/imported via CSV

For some types of models there will be a lot of records that are easier to edit offline in Excel or another spreadsheet program rather than through a web admin. It would be great to be able to export all the records for a given model as a CSV and then reimport to update.

Understandably this would get complicated with more complex field types and localization, but even if there were some limitations on it, a basic version of this would be useful.