I want to copy a folder with possibly some subfolders over a similarly
named folder, but if I do that using Nautilus' copy or move commands, I
will lose *all* 'extra' information from the target folder, as Nautilus
seems to crudely write over the folder instead of the contents of the
folders by simply first deleting the said target folder and then copying
the source folder.

Steps to reproduce the problem:
1. Duplicate an existing folder with files
2. Create a new file to duplicate folder
3. Copy 1st version over 2nd and see your new file being wiped out

Actual Results: You lose stuff that's not actually being overwritten but
just deleted (*and* deleted past the trash can - thus no undo).

Expected Results: Just the files that exist in both folders (and
matching subfolders) are deleted from the target directory before
copying from the source.

Additional Information: Fixing this is important as it's *not at all*
obvious to users what happened to their files in the target folder,
because it's counter-intuitive and very annoying (there's even no
undo!).

Also overcoming this problem, by just copying the files instead of
directories, can be a huge amount of work for the user if there are
lot's of subfolders (and sub-subfolders).