Backported vsync changes from new-netcode, WIP hull visibility culling

The hull culling functions are there, they just aren't being used right now because there are some annoying bugs.

Subsurface/Source/GUI/LoadingScreen.cs

@@ -101,6 +101,7 @@ namespace Barotrauma
 
             if (Hull.renderer != null)
             {
+                Hull.renderer.ScrollWater(deltaTime);
                 Hull.renderer.RenderBack(spriteBatch, renderTarget, 0.0f);
             }