VM with the hci-warn-before-shutdown flag. Minor changes to make the warnings for
rebooting and shutting down more consistent (preselect the No button for rebooting;
extended the Yes button text; modified warning text)
NewAction to use the Action<ActionBase> delegate instead of EventHandler. Thus
there is no need to fire them with Empty or null EventArgs and on several occasions
we avoid casting objects in the event handlers.
Signed-off-by: Konstantina Chremmou <konstantina.chremmou@citrix.com>
