Analysis options, fixes, and formatting (#110)

shrine/lib/home.dart

@@ -29,7 +29,7 @@ class ProductPage extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return ScopedModelDescendant<AppStateModel>(
-        builder: (BuildContext context, Widget child, AppStateModel model) {
+        builder: (context, child, model) {
       return AsymmetricView(
         products: model.getProducts(),
       );