Handling of wrong arguments for commands that have defaults

[y0014984]

If I use the following command:

crypto -m=encrypt -k=13 -a=column Teststring

I will get en encrypted string, that is encrypted with caesar algorithm and not with columnar algorithm. "columnar" would be the correct option. I think because this command defaults to "caesar", it will give no feedback that the given argument was wrong. We should change that. It's not critical but would help users with wrong commands.