Added option to toggle vsync

For the ultimate PC master race experience.

Also calling water scroll on every frame with deltatime instead of being called at fixed intervals, making it look smoother as framerate increases.

Subsurface/Source/Screens/GameScreen.cs

@@ -83,11 +83,6 @@ namespace Barotrauma
         /// <param name="gameTime">Provides a snapshot of timing values.</param>
         public override void Update(double deltaTime)
         {
-            if (Hull.renderer != null)
-            {
-                Hull.renderer.ScrollWater();
-            }
-
             //the accumulator code is based on this article:
             //http://gafferongames.com/game-physics/fix-your-timestep/
             Physics.accumulator += deltaTime;
@@ -173,8 +168,12 @@ namespace Barotrauma
 
         public override void Draw(double deltaTime, GraphicsDevice graphics, SpriteBatch spriteBatch)
         {
-            cam.UpdateTransform(true); 
-            
+            cam.UpdateTransform(true);
+
+            if (Hull.renderer != null)
+            {
+                Hull.renderer.ScrollWater((float)deltaTime);
+            }
             DrawMap(graphics, spriteBatch);
 
             spriteBatch.Begin();