Re-worked debug info, added logger coderef attr.

You can now provide a coderef as the logger attribute which will be called with
all debug messages / errors, so you can log them via your method of choice.

You can of course subclass Net::Joker::DMAPI and override C<_log> if you prefer,
but this attribute avoids that requirement.
Censor parameters we're going to log.

Don't make it easy for the user to accidentally log their Joker account password
or their customer's details in plain text somewhere silly.

Uses Data::Censor to do the censoring.
Add Data::Censor as a pre-req
Update Changes
Regenerated README
Bump version to 0.03