[WIP] Remove -C and -N vi compatibility arguments

Removing vi compatibility completely is currently blocked on getting the testdir/ tests working without it.

However, this pull request takes baby steps towards removing vi compatibility by removing the -C and -N command line arguments. Splitting up vi compatibility removal in multiple steps is probably the way forward, since the full removal task would be large for one pull request.
Will this give an error about an invalid argument? We probably should do that.