Use explicit cast to OsuGame rather than in-between derived classes.

# Conflicts:
#	osu.Game/GameModes/Menu/MainMenu.cs

osu.Game/GameModes/GameModeWhiteBox.cs

@@ -10,13 +10,12 @@
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.Transformations;
 using osu.Framework.Graphics.UserInterface;
-using osu.Game.Graphics.Containers;
 using OpenTK;
 using OpenTK.Graphics;
 
 namespace osu.Game.GameModes
 {
-    public class GameModeWhiteBox : OsuGameMode
+    public class GameModeWhiteBox : GameMode
     {
         private Button popButton;
 

osu.Game/GameModes/Menu/ButtonSystem.cs

@@ -19,7 +19,7 @@
 
 namespace osu.Game.GameModes.Menu
 {
-    public class ButtonSystem : OsuLargeContainer
+    public class ButtonSystem : LargeContainer
     {
         public Action OnEdit;
         public Action OnExit;
@@ -272,7 +272,7 @@ protected override void Update()
         /// <summary>
         /// osu! logo and its attachments (pulsing, visualiser etc.)
         /// </summary>
-        class OsuLogo : OsuContainer
+        class OsuLogo : AutoSizeContainer
         {
             private Sprite logo;
             private Container logoBounceContainer;
@@ -392,7 +392,7 @@ public FlowContainerWithOrigin()
         /// Button designed specifically for the osu!next main menu.
         /// In order to correctly flow, we have to use a negative margin on the parent container (due to the parallelogram shape).
         /// </summary>
-        private class Button : OsuContainer
+        private class Button : AutoSizeContainer
         {
             private Container iconText;
             private WedgedBox box;

osu.Game/GameModes/Menu/MainMenu.cs

@@ -17,7 +17,7 @@
 
 namespace osu.Game.GameModes.Menu
 {
-    internal class MainMenu : OsuGameMode
+    internal class MainMenu : GameMode
     {
         private ButtonSystem buttons;
         public override string Name => @"Main Menu";
@@ -28,9 +28,13 @@ public override void Load()
         {
             base.Load();
 
+            OsuGame osu = (OsuGame)Game;
+
             AudioSample welcome = Game.Audio.Sample.Get(@"welcome");
             welcome.Play();
 
+            //bgm = Game.Audio.Track.Get(@"circles");
+            //bgm.Start();
             Children = new Drawable[]
             {
                 new ParallaxContainer
@@ -52,7 +56,7 @@ public override void Load()
                                 }, ButtonSystem.EXIT_DELAY);
                             },
                             OnSettings = delegate {
-                                Game.Options.PoppedOut = !Game.Options.PoppedOut;
+                                osu.Options.PoppedOut = !osu.Options.PoppedOut;
                             },
                         }
                     }

osu.Game/Graphics/Background/Background.cs

@@ -7,10 +7,11 @@
 using osu.Game.Graphics.Containers;
 using OpenTK;
 using OpenTK.Graphics;
+using osu.Framework.Graphics.Containers;
 
 namespace osu.Game.Graphics.Background
 {
-    class Background : OsuLargeContainer
+    class Background : LargeContainer
     {
         protected Sprite BackgroundSprite;
 

osu.Game/Graphics/Containers/OsuContainer.cs

@@ -1,12 +0,0 @@
-//Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
-//Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
-
-using osu.Framework.Graphics.Containers;
-
-namespace osu.Game.Graphics.Containers
-{
-    class OsuContainer : AutoSizeContainer
-    {
-        public new OsuGameBase Game => base.Game as OsuGameBase;
-    }
-}

osu.Game/Graphics/Containers/OsuGameMode.cs

@@ -1,12 +0,0 @@
-//Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
-//Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
-
-using osu.Framework.GameModes;
-
-namespace osu.Game.Graphics.Containers
-{
-    public class OsuGameMode : GameMode
-    {
-        public new OsuGame Game => base.Game as OsuGame;
-    }
-}

osu.Game/Graphics/Containers/OsuLargeContainer.cs

@@ -1,12 +0,0 @@
-//Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
-//Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
-
-using osu.Framework.Graphics.Containers;
-
-namespace osu.Game.Graphics.Containers
-{
-    public class OsuLargeContainer : LargeContainer
-    {
-        public new OsuGameBase Game => base.Game as OsuGameBase;
-    }
-}

osu.Game/osu.Game.csproj

@@ -64,9 +64,6 @@
     <Compile Include="GameModes\Edit\SongSelectEdit.cs" />
     <Compile Include="Graphics\Background\Background.cs" />
     <Compile Include="Graphics\Containers\ParallaxContainer.cs" />
-    <Compile Include="Graphics\Containers\OsuContainer.cs" />
-    <Compile Include="Graphics\Containers\OsuGameMode.cs" />
-    <Compile Include="Graphics\Containers\OsuLargeContainer.cs" />
     <Compile Include="Graphics\Cursor\OsuCursorContainer.cs" />
     <Compile Include="Graphics\Processing\RatioAdjust.cs" />
     <Compile Include="Graphics\TextAwesome.cs" />