Reverted DisposableObject.cs to its original state

src/Umbraco.Core/DisposableObject.cs

@@ -21,8 +21,9 @@ namespace Umbraco.Core
         private readonly object _locko = new object();
 
         // gets a value indicating whether this instance is disposed.
-        // for internal tests only (not thread safe)
-        internal bool Disposed { get { return _disposed; } }
+        // for internal tests only (not thread safe)
+        //TODO make this internal + rename "Disposed" when we can break compatibility
+        public bool IsDisposed { get { return _disposed; } }
 
         // implements IDisposable
         public void Dispose()
@@ -32,12 +33,13 @@ namespace Umbraco.Core
         }
 
         // finalizer
-        ~DisposableObject()
-        {
-            Dispose(false);
-        }
+        ~DisposableObject()
+        {
+            Dispose(false);
+        }
 
-        private void Dispose(bool disposing)
+        //TODO make this private, non-virtual when we can break compatibility
+        protected virtual void Dispose(bool disposing)
         {
             lock (_locko)
             {