index.init() now uses the default catalog HTML template if one isn't passed in

lib/index_html.js

@@ -53,7 +53,7 @@ const back_links = {
   hasMember: "memberOf"
 };
 
-const default_template = path.join(__dirname, "defaults/catalog_template.html");
+
 
 const dont_back_link = new Set(Object.values(back_links));
 // TODO - Put this in a utility function
@@ -609,7 +609,7 @@ module.exports = function () {
       return html;
     },
 
-    init: function init(crate_data, out_path, multiple_files, template_path) {
+    init: function init(crate_data, out_path, multiple_files, template_path=defaults.catalog_template) {
       if (template_path) {
         var temp = fs.readFileSync(template_path, { encoding: "utf8" });
         this.template = ejs.compile(temp);