allow to use populate feature with custom route, either by:
1. set `populate: true` on route config: { controller: 'User', action: 'find', populate: true }
2. use query param `populate=fk1,fk2,...,fkn` with route config: { controller: 'User', action: 'find' }
3. use actionUtil.populateEach() in custom controller action with route config: { controller: 'User', action: 'customAction' }
Merge branch 'populate-in-action'