use GtkFileChooser in import LDIF/CSV dialog.
modified the spacing of the statusbar of address book.
fixed a crash when cancelling file selection dialog of vCard/JPilot by Escape key.
made the order of buttons comply with GNOME HIG.
reimplemented summary view with GtkTreeView.
replaced intl.h with glib/gi18n.h.
use GTK stock button for button set.
Initial import of Sylpheed (GTK2 version).