Add an 'expand' option for oauthFilter

[ilaif]

Requests are authenticated on any protected routes with the access_token, and an account is attached to 'req' when the authentication is successful. It is vital to add an 'expand' parameter to options in creation of oauthFilter to expand 'customData' for example since I use it almost in any route. Will reduce latency time of api calls in half.

Example:
var stormpathFilters = stormpathRestify.createFilterSet(stormpathConfig);
oauthFilter = stormpathFilters.createOauthFilter({expand: 'customData'});

Then I could do:
oauthFilter(req, res, function (err) {
console.log(req.account.customData);
});

Thanks in advance!
Ilai