Add myself as a contributor

CONTRIBUTORS.txt

@@ -162,3 +162,4 @@ Matthew Duggan, 2014/04/10
 Brian Bouterse, 2014/04/10
 Dmitry Malinovsky, 2014/04/28
 Luke Pomfrey, 2014/05/06
+Alexey Kotlyarov, 2014/05/16