status bars and code folding a user preference (bug #42306) * settings-dialog.ui: new checkboxes for status bars (main window and editor) and code folding * settings-dialog.cc (constructor): init new checkboxes from settings, (write-changed-settings): write boxes check states into settings * file-editor-tab.cc (constructor): do not set code folding here, (notice-settings): set code folding and show/hide status bar depending on settings * main-window.cc (notice-settings): show/hide status bar depending on settings