Reducing usage of #if CLIENT / #elif SERVER

The server will implement some classes it probably shouldn't need because certain items or game states depend on them.

BarotraumaServer/Source/Sprite/Sprite.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.Xna.Framework;
+
+namespace Barotrauma
+{
+    public partial class Sprite
+    {
+        private void LoadTexture(ref Vector4 sourceVector,ref bool shouldReturn)
+        {
+            //do nothing
+        }
+
+        private void CalculateSourceRect()
+        {
+            //do nothing
+        }
+
+        private void DisposeTexture()
+        {
+            //do nothing
+        }