show_lang: true, /* true, false: show/hide language menu */
show_sort: true, /* true, false: show/hide sort menu */
show_perpage: true, /* true, false: show/hide perpage menu */
+ show_switch: true, /* true, false: show/hide switch menu */
lang_options: ["en", "de", "da"],
/* display languages links for given languages, [] for all */
facets: ["xtargets", "subject", "author"],