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/Map/Levels/WaterRenderer.cs

@@ -74,10 +74,10 @@ namespace Barotrauma
             spriteBatch.End();
         }
 
-        public void ScrollWater()
+        public void ScrollWater(float deltaTime)
         {
-            wavePos.X += 0.0001f;
-            wavePos.Y += 0.0001f;
+            wavePos.X += 0.006f*deltaTime;
+            wavePos.Y += 0.006f*deltaTime;
         }
 
         public void Render(GraphicsDevice graphicsDevice, Camera cam, RenderTarget2D texture, Matrix transform)