fixed Tensor memory leak.

src/TensorFlowNET.Core/Sessions/BaseSession.cs

@@ -186,9 +186,10 @@ namespace Tensorflow
             var result = new NDArray[fetch_list.Length];
 
             for (int i = 0; i < fetch_list.Length; i++)
-            {
                 result[i] = fetchValue(output_values[i]);
-            }
+
+            for (int i = 0; i < feed_dict.Length; i++)
+                feed_dict[i].Value.Dispose();
 
             return result;
         }

src/TensorFlowNET.Core/Tensors/Tensor.Creation.cs

@@ -111,7 +111,7 @@ namespace Tensorflow
             // Free the original buffer and set flag
             Deallocator deallocator = (IntPtr values, IntPtr len, ref bool closure) =>
             {
-                Marshal.FreeHGlobal(dotHandle);
+                Marshal.FreeHGlobal(values);
                 closure = true;
             };