Add ssl option to connection

[roeltm]

Continuation of #147.

Went throught the comments from @IlyaSkriblovsky and tested it with the attached example code.

[IlyaSkriblovsky]

Thank you for the work! Just a couple of stylistic comments here.

Have you tested these changes in the real life?

[roeltm]

Have you tested these changes in the real life?

yes, for others if they want to test:

1. Generate a CA cert, and a certificate and key for the redis server (I used https://github.com/redis/redis/blob/unstable/utils/gen-test-certs.sh which generates all at once)
2. Run the redis server with the certificate
   redis-server --tls-port 6379 --port 0 --tls-cert-file ./tests/tls/redis.crt --tls-key-file ./tests/tls/redis.key --tls-ca-cert-file ./tests/tls/ca.crt
3. Run the ssl example script with the correct certificates

[IlyaSkriblovsky]

Thanks a lot! I will make a release on the weekend.

[roeltm]

@IlyaSkriblovsky When will you be able to release this?

[IlyaSkriblovsky]

@roeltm Done it, sorry for the delay