Setup config page widgets and options.

def setup_page(self):
        """Setup config page widgets and options."""
        settings_group = QGroupBox(_("Settings"))
        hist_spin = self.create_spinbox(
                            _("History depth: "), _(" entries"),
                            'max_entries', min_=10, max_=10000, step=10,
                            tip=_("Set maximum line count"))

        sourcecode_group = QGroupBox(_("Source code"))
        wrap_mode_box = self.create_checkbox(_("Wrap lines"), 'wrap')
        linenumbers_mode_box = self.create_checkbox(_("Show line numbers"),
                                                    'line_numbers')
        go_to_eof_box = self.create_checkbox(
                        _("Scroll automatically to last entry"), 'go_to_eof')

        settings_layout = QVBoxLayout()
        settings_layout.addWidget(hist_spin)
        settings_group.setLayout(settings_layout)

        sourcecode_layout = QVBoxLayout()
        sourcecode_layout.addWidget(wrap_mode_box)
        sourcecode_layout.addWidget(linenumbers_mode_box)
        sourcecode_layout.addWidget(go_to_eof_box)
        sourcecode_group.setLayout(sourcecode_layout)

        vlayout = QVBoxLayout()
        vlayout.addWidget(settings_group)
        vlayout.addWidget(sourcecode_group)
        vlayout.addStretch(1)
        self.setLayout(vlayout)