update to wabac.js 2.9.0-beta.0, smaller file size, loading improvements

ruffle: support for ruffle for flash loading, both hosted and in app
electron: update to latest beta (14) for latest chromium version
embed error messages: better error message when service worker can not be found
electron: build universal app for osx
bump to 1.5.0!

src/appmain.js

@@ -158,7 +158,8 @@ class ReplayWebApp extends LitElement
 
   renderNavBar() {
     return html`
-    <a href="#skip-main-target" @click=${this.skipMenu} class="skip-link">Skip main navigation</a>
+    ${IS_APP ? "" :
+    html`<a href="#skip-main-target" @click=${this.skipMenu} class="skip-link">Skip main navigation</a>`}
     <nav class="navbar has-background-info" aria-label="main">
       <div class="navbar-brand">
         ${!this.embed ? html`