add @oblalex to 'CONTRIBUTORS.txt' as proposed in pull request #3108

CONTRIBUTORS.txt

@@ -206,3 +206,4 @@ Mike Attwood, 2016/01/22
 David Harrigan, 2016/02/01
 Ahmet Demir, 2016/02/27
 Maxime Verger, 2016/02/29
+Alexander Oblovatniy, 2016/03/10