Refactor setupEntries and export route

Refactor setupEntries

Export route to use middleware like this
```
    var myapp = express();
    myapp.use(stubcell.route);
    var server = myapp.listen(9000);
```

Require merge [stubrec](https://github.com/yosuke-furukawa/stubrec/pull/1)
these checks should be in `./lib/check.js`.

```javascript
var check = require('./check');

if (check.request(entryReq, req)) {
  return entry;
}
```