[krbdev.mit.edu #6142] KerberosAgent dialogs jump around the screen

[Justin Anderson via RT]

As you progress through the various dialogs in the new KIM-aware KerberosAgent, they briefly 
flash at the bottom-left corner of the display before appearing in the center of the window.

Also, window position should be remembered per client for the duration of their interaction 
with KerberosAgent.