Could a --dry-run option be added to the git annex commands? Or, at least, to the most common ones like `git annex add`.

Given that there is no undo command, it would be nice to have the ability to simulate what git annex will do.

> [[wontfix|done]], see comments. Instead, options like --want-get and
> --want-drop can be used to simulate things. --[[Joey]]
