initial import

/cc @addyosmani 
This usage is a bit hard to follow. Would something like the following be possible?:

```js
var todomvc = require('todomvc-api');
var myApi = require('./');

gulp.task('test', function(done) {
  myApi.listen(8080, function() {
    // my api is running
    var apiServer = this;

    // default validation is localhost:8080
    todomvc.validate(function(err) {
      // close server.
      apiServer.close(done);
    });

    // accept server url override:
    todomvc.validate('http://0.0.0.0:9999', function(err) {/*...*/});
  });
});
```