Revert "remove GAS library"

This reverts commit f62c14291f.

gs/type/ImportJson.gs

@@ -578,4 +578,4 @@ function convertToBool_(map, key) {
     if (map[key] != null) {
         map[key] = toBool_(map[key]);
     }
-}
+}

gs/type/Interface.gs

@@ -0,0 +1,55 @@
+function EncodeUrlSlug(slug) {
+    return FilterLists.EncodeUrlSlug(slug);
+}
+
+function TrimUrlSlug(slug) {
+    return FilterLists.TrimUrlSlug(slug);
+}
+
+function GenerateHtmlViewLink(url, listName) {
+    return FilterLists.GenerateHtmlViewLink(url, listName);
+}
+
+function GenerateHtmlAddLink(url, listName) {
+    return FilterLists.GenerateHtmlAddLink(url, listName);
+}
+
+function GenerateHtmlHomeLink(url, listName) {
+    return FilterLists.GenerateHtmlHomeLink(url, listName);
+}
+
+function GenerateHtmlGuideLink(url, listName) {
+    return FilterLists.GenerateHtmlGuideLink(url, listName);
+}
+
+function GenerateHtmlForumLink(url, listName) {
+    return FilterLists.GenerateHtmlForumLink(url, listName);
+}
+
+function GenerateHtmlIssuesLink(url, listName) {
+    return FilterLists.GenerateHtmlIssuesLink(url, listName);
+}
+
+function GenerateHtmlEmailLink(url, listName) {
+    return FilterLists.GenerateHtmlEmailLink(url, listName);
+}
+
+function GenerateHtmlForksCombosLink(forkComboListName) {
+    return FilterLists.GenerateHtmlForksCombosLink(forkComboListName);
+}
+
+function GenerateHtmlChangelogLink(url, listName) {
+    return FilterLists.GenerateHtmlChangelogLink(url, listName);
+}
+
+function GenerateHtmlDonateLink(url, listName) {
+    return FilterLists.GenerateHtmlDonateLink(url, listName);
+}
+
+function GetLastUpdated(urlToCheck) {
+    return FilterLists.GetLastUpdated(urlToCheck);
+}
+
+function GenerateHtmlListName(listName) {
+    return FilterLists.GenerateHtmlListName(listName);
+}