#39 Make append function more useful

[i30817]

Currrently append has to rename the directory if it conflicts with a already existing one even if the files are different. I was thinking that this makes the append function much less useful than it could be.

I'm not asking for complete file shadowing replacement (though it would be nice), but having a way to insert new files on existing dirs would be nice. Maybe something to do with the proposed function to not compress the directory tree?