Allow the sidebar config functions to accepts args

lib/config.php

@@ -20,6 +20,12 @@ function roots_display_sidebar() {
     /**
      * Conditional tag checks (http://codex.wordpress.org/Conditional_Tags)
      * Any of these conditional tags that return true won't show the sidebar
+     *
+     * To use a function that requires parameters, use the following format:
+     *
+     * array('function_name', array('arg1', 'arg2'))
+     *
+     * The second element must be an array even if there's only 1 argument.
      */
     array(
       'is_404',

lib/sidebar.php

@@ -29,7 +29,11 @@ class Roots_Sidebar {
   }
 
   private function check_conditional_tag($conditional_tag) {
-    return $conditional_tag();
+    if (is_array($conditional_tag)) {
+      return call_user_func_array($conditional_tag[0], $conditional_tag[1]);
+    } else {
+      return $conditional_tag();
+    }
   }
 
   private function check_page_template($page_template) {