Merge pull request #6 from kevin39/master

Greylisted expected codes fix.
Increased default RSET timeout - fixes #7
Misc enhancements & fixes

* 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