* regexxer.schemas.in (override_direction): Remove configuration
option because it doesn't seem to be necessary anymore.  That is,
the current GTK+ release gets the direction of Latin text in RTL
locales right now.

* src/globalstrings.h (conf_key_override_direction): Remove.
* src/mainwindow.cc (MainWindow::on_conf_value_changed): Remove
the code that handles the "override_direction" config option.
* src/prefdialog.{cc,h} (PrefDialog): ditto.
* ui/prefdialog.glade (button_override_direction): Remove.