Add a save function

SpriteLibrary/SpriteDatabase.cs

@@ -40,6 +40,22 @@ namespace SpriteLibrary
             LoadSpriteInfo();
         }
 
+        internal void Save()
+        {
+            if(!DoesResourceExist(Filename))
+            {
+                //we will try to save it as a file
+                try
+                {
+                    WriteToXmlFile<List<SpriteInfo>>(Filename, SpriteInfoList);
+                }
+                catch (Exception e)
+                {
+                    throw new Exception("SpriteDatabase failed to save: Filename:" + Filename +"\n" + "ERROR: " + e.ToString(), e);
+                }
+            }
+        }
+
         public void SetSnapGridSize(Size GridSize)
         {
             if (GridSize.Width <= 0) return;