Allow other objects to be exported in test files.

More flexible test files, for my test suite I wanted to export other objects from the same test file (module) and vows did not like that idea as it tries to run every object that is exported by the module as a test.

There are several other reasons why one would want to export from within the same file, ofc the main one is to keep the project structure clean. I could have split the files but going from 1 to 2/3 files is just cumbersome and a small change inside vows was easier to deal with.

Example test file:
```javascript
var complexVar = {};
var complexTest = function () {};

vows.describe('The Good Things').addBatch({
    'A strawberry': {
        topic: new(Strawberry),
        'is red': function (strawberry) {
            var color = complextTest(strawberry);
            assert.equal (color, '#ff0000');
        }
    }
}).export(module);

module.exports.var = complexVar;
module.exports.test = complexTest;
```

If I missed something and there is a cleaner way to do this already, feel free to point it out to me.