Add support for new handshake protocol

[watfordjc]

This pull request is regarding #81 and merges the new handshake protocol proof of concept by @chriswheeldon, along with the retry loop mentioned in my comment on the issue, and adds the new protocol as a fallback to the previous protocol.

1. The changes add a few new dependencies that might not be installed on a system already using the script/program.
   • I have not updated version = 0.4.
2. The protocol change requires setting a Kaza/TP-Link Cloud e-mail and password if the smart device is connected to the cloud.
   • Configuration file command argument (and parsing) and/or email/username/password command arguments have not been introduced.
   • Splitting user_hash into a separate script/program and adding a user_hash command line option may be preferable.
3. The discovery protocol has not been included.
   • A discover/scan command line option (or separate script/utility) as well as related options (such as binding IP address) might be preferable.
4. The classes are inline as I very seldom write python code and am not sure whether or not this repository prefers self-contained code.
5. As this script/program is called for a single request/response, the use of persistent connections using the new protocol was not considered.
6. Each retry in the retry loop adds a 0.25 second delay and the number of retries was arbitrarily chosen (I felt 2 seconds of failure should result in failure). This may need tweaking (or removing if the cause of failure can be discerned).
7. I have done minimal tests (-c info, -c on, -c off) with two HS110 that use the old protocol, two HS110 that use the new protocol, and a KL130B (-c info only) that uses the old protocol.