Fix current dirnames.
Fix current dirnames.

For example, if we have the following architecture:

    Main.xyl
    A/
        Overlay.xyl
        B/
            Fragment.xyl

Main.xyl has a:

    <?xyl-overlay href="A/Overlay.xyl"?>

and Overlay.xyl has a:

    <?xyl-fragment href="B/Fragment.xyl"?>

Before, B/Fragment.xyl was resolved from the current directory of
Main.xyl instead of the one of Main.xyl. Now it is as expected :-).

vcgato29/Central,vcgato29/Central,Metalaka/Central,Grummfy/Central,Metalaka/Central,Grummfy/Central