the visible of a stack

[Chipp Walters]

This one's better as it checks all the monitor screens (and has the
blendlevel fix)

function isStackCurrentlyVisibleOnAnyMonitor pStack
   --> pStack IS THE SHORT NAME OF STACK
   set wholematches to true
   if pStack is among the lines of windows() then
      if the blendlever of stack pStack = 100 then return false
      repeat for each line L in the screenrects
         if the topLeft of stack pStack is within L then return true
         if the bottomright of stack pStack is within L then return true
      end repeat
      return false
   else
      return false
   end if
end isStackCurrentlyVisibleOnAnyMonitor