Tags: patch

`project-find-file' and related commands share their history with more
general commands like `find-file', so they should add the absolute file
name to history.  Currently, file names relative to the project root are
added.  The attached patch fixes this.

I've also replaced `concat' with `expand-file-name' at a certain point.
I see no reason why one shouldn't do that, but please have a look.