Require at least Safari 11 (#683)

Safari 11 is shipped with High Sierra.

src/app.ts

@@ -77,7 +77,7 @@ angular.module('3ema', [
     FF: 50,
     CHROME: 45,
     OPERA: 32,
-    SAFARI: 10,
+    SAFARI: 11,
 })
 
 // Set default route