iOS homescreen improvements

Closes #345

app/index.html

@@ -15,6 +15,15 @@
 
   <link rel="icon" href="favicon.ico" type="image/x-icon" />
 
+  <link rel="apple-touch-icon" href="img/icons/icon90.png">
+  <link rel="apple-touch-icon" sizes="90x90" href="img/icons/icon90.png">
+  <link rel="apple-touch-icon" sizes="120x120" href="img/icons/icon120.png">
+
+  <meta name="apple-mobile-web-app-title" content="Webogram">
+  <meta name="mobile-web-app-capable" content="yes">
+  <meta name="apple-mobile-web-app-capable" content="yes">
+  <meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
+
   <meta property="og:title" content="Webogram">
   <meta property="og:url" content="http://zhukov.github.io/webogram/">
   <meta property="og:image" content="http://zhukov.github.io/webogram/img/logo_share.png">