Displays a modal message dialog box to the user.
t is one of 'ok 'okcancel 'abortretryignore 'yesnocancel 'yesno 'retrycancel 'canceltrycontinue
m is one of
i is one of 'information 'exclamation 'hand 'stop 'question 'asterisk 'warning 'error
c is the caption str, if any.
r is one of 'none 'reject 'accept 'deleted 'ok 'cancel 'close 'yes 'no 'apply 'help 'unknown
bodyText is the text of the body (a Str)