Moved all tests to using mocha.

* Added devDependencies
* Generate mocha tests dynamically from old json cases
Removed old tests
Added some more tests.

Mainly for lib/connection and lib/mqtt
Added tests for QOS.

Inspired by comments in issue #18
Added tests for TLS Client.

Only does a simple connect
Included self signed certs.
Smarter port assignment so it minimize the risk of EADDRINUSE
Merge pull request #31 from kmpm/mocha

Moved all tests to using mocha.