Further separation of client-specific code

Still not done here, just gonna push a commit now so I can pull this from elsewhere.

BarotraumaClient/Source/GameSession/GameModes/Tutorials/TutorialMode.cs

@@ -0,0 +1,53 @@
+using Microsoft.Xna.Framework.Graphics;
+using Barotrauma.Tutorials;
+
+namespace Barotrauma
+{
+    class TutorialMode : GameMode
+    {
+        public TutorialType tutorialType;
+        
+        public static void StartTutorial(TutorialType tutorialType)
+        {
+            Submarine.MainSub = Submarine.Load("Content/Map/TutorialSub.sub", "", true);
+            
+            tutorialType.Initialize();
+        }
+
+        public TutorialMode(GameModePreset preset, object param)
+            : base(preset, param)
+        {
+        }
+
+        public override void Start()
+        {
+            base.Start();
+
+            tutorialType.Start();
+
+        }
+
+        public override void AddToGUIUpdateList()
+        {
+            tutorialType.AddToGUIUpdateList();
+        }
+
+        public override void Update(float deltaTime)
+        {
+            base.Update(deltaTime);
+
+            tutorialType.Update(deltaTime);
+
+        }
+
+
+        public override void Draw(SpriteBatch spriteBatch)
+        {
+            base.Draw(spriteBatch);
+
+            //CrewManager.Draw(spriteBatch);
+            tutorialType.Draw(spriteBatch);
+        }
+
+    }
+}