Fix SliceStream.Seek offset check (#19)

* Fix SliceStream.Seek offset check

Suppose that SliceStream has zero length. At the creation `Position` will have value `0` and. The check in `Seek` method would prevent reassigning the `0` to `Position` property which should be perfectly valid.

* Fix the exception message too

Author: filipnavara

src/LibObjectFile/Utils/SliceStream.cs

@@ -91,7 +91,7 @@ public override long Seek(long offset, SeekOrigin origin)
             }
 
             if (newPosition < 0) throw new ArgumentOutOfRangeException(nameof(offset), $"New resulting position {newPosition} is < 0");
-            if (newPosition >= _length) throw new ArgumentOutOfRangeException(nameof(offset), $"New resulting position {newPosition} is >= Length {_length}");
+            if (newPosition > _length) throw new ArgumentOutOfRangeException(nameof(offset), $"New resulting position {newPosition} is > Length {_length}");
 
             // Check that we can seek on the origin stream
             _baseStream.Position = _basePosition + newPosition;
@@ -145,4 +145,4 @@ public override void Write(byte[] buffer, int offset, int count)
             }
         }
     }
-}
+}