Fix behaviour of commit.
It's now a fatal error if the option to --logfile isn't readable.
Ditto if both --message and --logfile are specified.
Is there an error message when trying to diff non-existing files?
found: No such file or directory
not: No such file or directory
Is there an error message when trying to add non-existing files?
found: No such file or directory
not: No such file or directory