SMTP: don't create new Transaction at disconnect

the current result of passing a DENY* response is a new transaction. That seems wrong.
Merge pull request #106 from msimerson/disconnect

SMTP: don't create new Transaction at disconnect
Q::hooks(), accept a hook name argument

and return a useful result
Merge pull request #108 from msimerson/hooks

Q::hooks(), accept a hook name argument
Merge pull request #109 from msimerson/master

updated MANIFEST
remove test counters from plugin tests

replace with done_testing(), which provides the same "make sure to kvetch if tests fail to run" without requiring humans to do the bookkeeping.