Added Citrix Viewer to the list of exceptions for PC-Style Home/End handling

Hi,

I have added Citrix Viewer to the list of exceptions for PC-Style Home/End handling. There's not much to explain, Citrix Viewer is a remote desktop access application and so it makes sense to add it to the excluded list just like any other application that is already there.

I tested the change and it works fine, i.e. when logged remotely using Citrix Viewer I can now observe proper Home/End behavior.