Mobile app initial implementation.

Closes #3 (closed)

lib/src/screens/home.dart

@@ -25,9 +25,11 @@ class _HomeState extends State<Home> {
   @override
   initState() {
     super.initState();
-    setState(() {
-      _host = widget.host;
-    });
+    if (widget.host != null) {
+      setState(() {
+        _host = widget.host;
+      });
+    }
 
     showMode(widget.mode);