* debian/{preinst,postint,postrm}: cleanup, remove natty-specific code, and also gdm-specific code now that we use lightdm by default. * usr/share/xubuntu/session.sh: dropped, now that x11-common sets the needed XDG vars, using startxfce4 is enough. * usr/share/xsessions: - xubuntu.desktop.in, po/: dropped, not needed anymore. - xubuntu.desktop: added, generated from xfce.desktop. * debian/control: - reword descriptions. - recommends xfce4-utils, and either lightdm or gdm. * usr/share/xubuntu/applications/defaults.list: updated for the latest seed changes.