error fix + embedding extensability (#110)

* embed mode: make embedding options more extensible
ui: unify service worker not available errors, show same error in standard/embed mode, including when loaded over http
- more customizations for extended embed, allow hiding 'browse contents' button
- simplify title updates
- make error page / icon more customizable
- autoupdating in editable mode: don't update if previous one didn't finish, make customizable, don't autoupdate at all over >=100 pages

* dependencies: update ruffle to 2022-07-02

* bump to 1.6.1, update CHANGELIST

src/story.js

@@ -2,7 +2,7 @@ import { LitElement, html, css, unsafeCSS } from "lit";
 import { wrapCss } from "./misc";
 
 import { unsafeHTML } from "lit/directives/unsafe-html.js";
-import marked from "marked";
+import { marked } from "marked";
 
 import { getTS, getReplayLink } from "./pageutils";