Allow for pinning and hiding monitors during rearranging in montage

[pliablepixels]

a) For folks who have many monitors, its a pain tapping the eye icon and hiding monitors - its much more intuitive to hide then while dragging/dropping them around in edit mode as its visually more mappable

b) When organizing monitors in montage, its useful to "pin" some monitors to the screen so their locations don't change when you move other monitors around