added front page samples to testing, plus a couple of tweaks to front page and code lab

src/tests/site/code/types_yes.dart

Index: src/tests/site/code/types_yes.dart
diff --git a/src/tests/site/code/types_yes.dart b/src/tests/site/code/types_yes.dart
index 022d31237522d22b13908c404995809c5d06e13b..c74148aaa9848ffcfded355e2cf5d29333557ed2 100644
--- a/src/tests/site/code/types_yes.dart
+++ b/src/tests/site/code/types_yes.dart
@@ -1,11 +1,10 @@
-// With types (and an optional parameter).
-num recalculate(Point origin,
-                num offset,
-                {bool estimate:false}) {
-  // ...
+import 'dart:math' show Point;
+
+void main() {
+  print('Hello, World!');
+//  recalculate(1, 'bob', 3);
 }
 
-class Point {
-  num x;
-  num y;
-}
+num recalculate(Point origin, num offset, {bool estimate: false}) {
+  // ...
+}