* src/filetree.cc (FileTree::find_recursively): Replace uses of
Glib::filename_display_name() by Glib::filename_display_basename()
to enable translation of well-known locations in future.  Store
the full path in the directory stack.
(FileTree::find_fill_dirstack): Convert the full path from the
stack to a displayable name with Glib::filename_display_basename().
(FileTree::save_file_at_iter): Determine the basename for
use in the error message with Glib::filename_display_basename().

* src/mainwindow.cc (MainWindow::set_title_filename): Call
Glib::filename_display_basename() to get the filename to be
displayed in the window title.

* src/filetreeprivate.{cc,h}: Some early spring cleaning.

svn path=/trunk/; revision=630