testing fixtures

Need to create a system where the users can add data to a fixture that can be used in the testing of their app.
Having a global list of fixtures might cause unwanted things. I think it be better if people could have different 'instances' of the testing module. I think would could maybe work would be to have this module be a function:

```javascript
module.exports = function() {
    // insert current stuff here
};
```

Then usage in tests would look something like:

```
describe("...", function() {
    var locations;

    beforeEach(function() {     
        ...
        locations = LocationState.testing();
        ...
    });
});
```