Don't break the call chain in the fetch

[omeralper]

I think this should be
if( this.getToken() ){
// we'll be using the supplied access token
Backbone.Model.prototype.fetch.call( self ,options);
}

instead of

if( this.getToken() ){
// we'll be using the supplied access token
Backbone.Model.prototype.fetch.call( self );
}

[tracend]

Sure, maybe even:

Backbone.Model.prototype.fetch.apply( self, arguments );

Feel free to send in a pull request