Updated authors file with Aziz Köksal for the tests/path.py file

He allowed us to release the tests/path.py file under the MIT license a while ago https://groups.google.com/group/python-virtualenv/msg/ea453f14a2cd1329?dmode=source&output=gplain&noredirect&pli=1

AUTHORS.txt

@@ -4,6 +4,7 @@ Alexandre Conrad
 Andrey Bulgakov
 Antti Kaihola
 Armin Ronacher
+Aziz Köksal
 Brian Rosner
 Carl Meyer
 Chris McDonough