Prefs Frameword demo overlay has broken link to demo code

The prefs framework demo
http://build.fluidproject.org/infusion/demos/prefsFramework/
has a broken link for the 'demo code' link in the overlay. It is currently referencing
https://github.com/fluid-project/infusion/tree/master/src/demos/prefsFramework
This wasn't properly updated when we restructured the code, and it should point to
https://github.com/fluid-project/infusion/tree/master/demos/prefsFramework