inject_on_import.mdwn

Would it be possible to add an `--inject` option to import?

Say, for example, I have an annex on computer A which has a subset of files and a directory of files which are potentional duplicates of files in the annex.

I would like to do something like this:

    mkdir ~/annex/import
    cd ~/annex/import
    git annex import --deduplicate --inject ~/directory/of/files

This would do the same as `--deduplicate`, except if the file is not present in the annex, it would be injected. For example:

Annex knows about A and B, A is present but B is not.
$DIR contains A, B and C.

A would be deleted from $DIR due to `--deduplicate`.
B would be injected into the repo (making it present) due to `--inject`, then deleted from $DIR.
C would be added to the annex, resulting in this

    $ ls ~/annex/import
    C