Rename App to MaterialApp

MaterialApp assumes that you're using material design.

Also move radial reaction and fix imports for stats box.

examples/game/example_effect_line.dart

diff --git a/examples/game/example_effect_line.dart b/examples/game/example_effect_line.dart
index 05323d0..6d05848 100644
--- a/examples/game/example_effect_line.dart
+++ b/examples/game/example_effect_line.dart
@@ -53,7 +53,7 @@
   ];
 
   Widget build(BuildContext context) {
-    return new App(
+    return new MaterialApp(
       title: 'EffectLine Demo',
       theme: _theme,
       routes: {

examples/game/lib/main.dart

diff --git a/examples/game/lib/main.dart b/examples/game/lib/main.dart
index 9150ab9..098f3eb 100644
--- a/examples/game/lib/main.dart
+++ b/examples/game/lib/main.dart
@@ -81,7 +81,7 @@
   int _lastScore = 0;
 
   Widget build(BuildContext context) {
-    return new App(
+    return new MaterialApp(
       title: 'Asteroids',
       theme: _theme,
       routes: {

examples/game/test_bed.dart

diff --git a/examples/game/test_bed.dart b/examples/game/test_bed.dart
index 653a566..b2dc7fb 100644
--- a/examples/game/test_bed.dart
+++ b/examples/game/test_bed.dart
@@ -32,7 +32,7 @@
   runApp(_app);
 }
 
-class TestBedApp extends App {
+class TestBedApp extends MaterialApp {
 
   Widget build() {
     ThemeData theme = new ThemeData(

examples/game/test_drawatlas.dart

diff --git a/examples/game/test_drawatlas.dart b/examples/game/test_drawatlas.dart
index dba1748..edf568e 100644
--- a/examples/game/test_drawatlas.dart
+++ b/examples/game/test_drawatlas.dart
@@ -32,7 +32,7 @@
   String json = await _bundle.loadString('assets/sprites.json');
   _spriteSheet = new SpriteSheet(_images['assets/sprites.png'], json);
 
-  runApp(new App(
+  runApp(new MaterialApp(
     title: 'Test drawAtlas',
     theme: _theme,
     routes: {

examples/game/test_performance.dart

diff --git a/examples/game/test_performance.dart b/examples/game/test_performance.dart
index 5ceab23..44d363c 100644
--- a/examples/game/test_performance.dart
+++ b/examples/game/test_performance.dart
@@ -33,7 +33,7 @@
   String json = await _bundle.loadString('assets/sprites.json');
   _spriteSheet = new SpriteSheet(_images['assets/sprites.png'], json);
 
-  runApp(new App(
+  runApp(new MaterialApp(
     title: 'Test Sprite Performance',
     theme: _theme,
     routes: {

examples/game/test_physics.dart

diff --git a/examples/game/test_physics.dart b/examples/game/test_physics.dart
index 137a325..4c2ecc1 100644
--- a/examples/game/test_physics.dart
+++ b/examples/game/test_physics.dart
@@ -27,7 +27,7 @@
   String json = await _bundle.loadString('assets/sprites.json');
   _spriteSheet = new SpriteSheet(_images['assets/sprites.png'], json);
 
-  runApp(new App(
+  runApp(new MaterialApp(
     title: 'Test Physics',
     theme: new ThemeData(
       brightness: ThemeBrightness.light,