ENH: Update CTK

$ git shortlog b643fd8..e771b4a --no-merges
Jean-Christophe Fillion-Robin (2):
Do not override widget visibility if already set in a layout view factory
Do not require QWidget in decorator generated by ctkWrapPythonQt

Julien Finet (4):
Fix compilation error with Qt < 5.2.1
Add Qt5 support for VTK.
Add Qt5 support to QtTesting module
Fix ctkFileDialogEventTranslatorPlayerTests

Sascha Zelzer (6):
Added application support and improved debugging mechanism.
Fixed installing plug-ins via symbolic names.
Fixed class / struct forward decls and incomplete type.
Improved test output.
Visual Studio seems to need the full class definition.
During shutdown of the plugin framework, also stop all plug-ins.

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24205 3bd1e089-480b-0410-8dfb-8563597acbee