Added base classes to encapsulate metadata in media

Aurora/Backend/Models/Media/BaseMedia.cs

@@ -0,0 +1,54 @@
+using System;
+using System.IO;
+
+namespace Aurora.Backend.Models.Media
+{
+    public abstract class BaseMedia
+    {
+        private bool _loaded;
+        private Stream _stream;
+
+        public BaseMedia()
+        {
+            _loaded = false;
+            Id = Guid.NewGuid().ToString();
+        }
+
+        #region Properties
+        public string Id { get; private set; }
+
+        #endregion Properties
+
+        public virtual void Load()
+        {
+            _loaded = true;
+        }
+
+        public virtual void Unload()
+        {
+            _loaded = false;
+        }
+
+        public abstract MediaTypeEnum MediaType { get; }
+
+
+        /// <summary>
+        /// Gets or sets the data stream that holds the song.
+        /// </summary>
+        /// <value>The data stream.</value>
+        public Stream DataStream
+        {
+            get
+            {
+                return _stream;
+            }
+            protected set
+            {
+                if (value != _stream)
+                {
+                    _stream = value;
+                }
+            }
+        }
+    }
+}