Hide columns on ODS rollingstock import #49
Description
When importing from ODS sheets, column and row selection might confuse the user.
So set a standard table layout and make it default.
Then hide these options under "Advanced Options" so expert users with non-default table layout can still import them.
Also for column selection, show letters in QSpinBox, like colimn 1 -> A, column 2 -> B etc...