Compass Tests V2

Ok once again I just want to use this PR to discuss some stuff. It's in no way ready to merge

https://github.com/rwaldron/johnny-five/issues/200
["HMC6352", "HMC5883L"].forEach(function(model) {

  exports[model] = {
    setUp: function(done) {
      this.compass = new Compass({
        device: model
      });
    }
    ... 
  };

});
```

What about that?