Update contributor list.

Docs/Urho3D.dox

@@ -77,6 +77,7 @@ Urho3D development, contributions and bugfixes by:
 - Danny Boisvert
 - Sergey Bosko
 - Lisandro Bruzzo
+- Steven Burns
 - Thomas Böhm
 - Carlo Carollo
 - Pete Chown

README.md

@@ -31,6 +31,7 @@ Urho3D development, contributions and bugfixes by:
 - Danny Boisvert
 - Sergey Bosko
 - Lisandro Bruzzo
+- Steven Burns
 - Thomas Böhm
 - Carlo Carollo
 - Pete Chown