Add quote special form

src/special.c

@@ -101,3 +101,7 @@ struct ucl_object *ucl_special_setq(struct ucl_state *state, struct ucl_object *
 struct ucl_object *ucl_special_progn(struct ucl_state *state, struct ucl_object *args) {
     return ucl_progn(state, args);
 }
+
+struct ucl_object *ucl_special_quote(struct ucl_state *state, struct ucl_object *args) {
+    return ucl_car(args);
+}