0.1.11:
- Handling IDNA errors

0.1.10:
- Handling the NoNameservers exception

0.1.9:
- Handling DNS timeout + YXDOMAIN

0.1.8:
- Added IDNA domain handling. (might need adjustment when
  https://bugs.python.org/issue20083 gets fixed)

0.1.7:
- Handle the SMTPServerDisconnected exception throughout all the SMTP
  connection. Try to contact all MXes for a successful probe.

0.1.6:
- Fixed a rare case where aol.co returns '.' in MX that causes an
  exception for the SMTP module, with added tests.

0.1.5:
- Handle socket errors (https://docs.python.org/3/library/
  socket.html#exceptions)

0.1.4:
- Handle 'No MX record' exception

0.1.3:
- Added ambigious (4xx) response code handling
