Correct LoggingAffix's logging method

(1) It requires a reference to `self`
(2) We need to concatenate a few tuples before using `*(....)` on
them when we call Repy's `log` function.
Add dy_import so BaseAffix can use affix_exceptions.AffixError
Add `copy` method to LoggingAffix.
Simple unit test for LoggingAffix (calling all methods)