Add suite for testing secure connections to the server

The tests make sure that clients that want to use SSL 3.0 will be rejected
and those using TLS (1.0, 1.1, 1.2) will be accepted.
Use customized escalus from the branch

NOTE: This commit is not intended to be merged!
Merge pull request #84 from esl/secured_connections

Add suite for testing secure connections to the server