Kiosk mode

[Jasper Huijsmans]

Hey,

I just noticed benny created support for locking down features (kiosk mode)
and implemented it for the panel. This is an extremely cool feature! Benedikt,
you rock!

Personally, I hope we can use this in all relevant Xfce modules. It would make
for some awesome marketing for the new release (New! With ultimate permission
control system for your bussiness environment! ;-).

	Jasper