- msg() now returns an int (e.g. 0 for OK, non-zero otherwise)
- add msgf() a printf-style version of msg()
- add confirm() a printf-stle yes/no dialog (returns TRUE on "Yes"/default)
- add deny() a printf-style no/yes dialog (returns TRUE on "No"/default)
- add yesNoOpts to allow application to over-ride "Yes"/"No" strings.