This adds the ability to connect to TLS-protected queue brokers, via the 'protocol' option. Update affected unit tests, add functional test (verified against activemq v5.15.0). Also document how to run the functional tests

tree dependency is not found in trusty - two options to fix: 'apt update' before installing tree, or don't install it. I chose the latter because it does not look like it is being used

I was able to somewhat replicate the activemq install issue with the ubuntu:trusty docker image, and an 'apt update' resolved it