Removed NioTSO client and server

- NioTSO client isn't needed because we're using RayLib
- Added FreeSO's API server to handle most backend operations

server/tso.common/Rendering/CachableTexture2D.cs

@@ -0,0 +1,88 @@
+using FSO.Common.Utils;
+using Microsoft.Xna.Framework.Graphics;
+using System;
+
+namespace FSO.Common.Rendering
+{
+    public class CachableTexture2D : Texture2D, ITimedCachable
+    {
+        /// <summary>
+        /// Creates a new texture of the given size
+        /// </summary>
+        /// <param name="graphicsDevice"></param>
+        /// <param name="width"></param>
+        /// <param name="height"></param>
+        public CachableTexture2D(GraphicsDevice graphicsDevice, int width, int height)
+            : base(graphicsDevice, width, height)
+        {
+        }
+        /// <summary>
+        /// Creates a new texture of a given size with a surface format and optional mipmaps 
+        /// </summary>
+        /// <param name="graphicsDevice"></param>
+        /// <param name="width"></param>
+        /// <param name="height"></param>
+        /// <param name="mipmap"></param>
+        /// <param name="format"></param>
+        public CachableTexture2D(GraphicsDevice graphicsDevice, int width, int height, bool mipmap, SurfaceFormat format)
+            : base(graphicsDevice, width, height, mipmap, format)
+        {
+        }
+        /// <summary>
+        /// Creates a new texture array of a given size with a surface format and optional mipmaps.
+        /// Throws ArgumentException if the current GraphicsDevice can't work with texture arrays
+        /// </summary>
+        /// <param name="graphicsDevice"></param>
+        /// <param name="width"></param>
+        /// <param name="height"></param>
+        /// <param name="mipmap"></param>
+        /// <param name="format"></param>
+        /// <param name="arraySize"></param>
+        public CachableTexture2D(GraphicsDevice graphicsDevice, int width, int height, bool mipmap, SurfaceFormat format, int arraySize)
+            : base(graphicsDevice, width, height, mipmap, format, arraySize)
+        {
+
+        }
+
+        private bool WasReferenced = true;
+        public bool BeingDisposed = false;
+        private bool Resurrect = true;
+        public object Parent; //set if you want a parent object to be tied to this object (don't kill parent til we die)
+        ~CachableTexture2D() {
+            if (!IsDisposed && !BeingDisposed)
+            {
+                //if we are disposed, there's no need to do anything.
+                if (WasReferenced)
+                {
+                    TimedReferenceController.KeepAlive(this, KeepAliveType.DEREFERENCED);
+                    WasReferenced = false;
+                    GC.ReRegisterForFinalize(this);
+                    Resurrect = true;
+                }
+                else
+                {
+                    BeingDisposed = true;
+                    GameThread.NextUpdate(x => this.Dispose());
+                    GC.ReRegisterForFinalize(this);
+                    Resurrect = true; //one more final
+                }
+            }
+            else { Resurrect = false; }
+        }
+
+        public void Rereferenced(bool saved)
+        {
+            WasReferenced = saved;
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing) base.Dispose(disposing);
+            else if (Resurrect)
+            {
+                //in finalizer
+                GC.ReRegisterForFinalize(this);
+            }
+        }
+    }
+}