Add a generic test-runner.

I think it would be useful to have a generic test-runner that can be used without mocha.  This is a super-basic version, you just give it the name of a module and it executes each method on that module in turn.

(I also changed the LoadsSocket class to use an options hash rather than a list of parameters, this seems to be more in keeping with standard javascript practice when there more than one or two args).