Misc enhancements & fixes

Some bug fixes. Tested in production over 1.5 million email addresses all over the world.

* Timeout improved after intensive tests
* Log attribute set to public for debug purposes
* Ability to disable catch all testing (catchall_test)
* Timeout are now catched properly (flag email as valid) in case
to accept down in case to avoid false positive
* Better support for RSET, NOOP and QUIT on weird RFC
implementations
* Added catch to handle empty/non-response