WIP: add mocha tests; enable CI build

[mojavelinux]

• add a test suite based on mocha and chai
• enable the Travis CI build
• configure the SSH identity in the CI build so tests will run

[mojavelinux]

This is a start. I'm still working on making the build green and adding tests for all the commands.

[mojavelinux]

I wasn't quite done. I'll send another PR because I have a lot more tests and a better setup.

[mojavelinux]

In the meantime, can you enable the Travis CI build in the upstream?

I'll also reeanble the other versions of node. I just had them disabled to speed up the turnaround.