Set Qt branch to 4.6.0

diff --git a/src/3rdparty/qt b/src/3rdparty/qt
index 0828c69ad805406568f6eef2bffbbd54b04dea41..d16ba0a93d611689bce9a2732a1cc8c9a317f5bf 160000 (submodule)
--- a/src/3rdparty/qt
+++ b/src/3rdparty/qt
@@ -1 +1 @@
-Subproject commit 0828c69ad805406568f6eef2bffbbd54b04dea41
+Subproject commit d16ba0a93d611689bce9a2732a1cc8c9a317f5bf