Include angle-grinder

- [x] remove old `angle-grinder`
- [x] include new angle-grinder via git submodule
- [x] load new resources
- [x] create basic grid for users
- [x] find `restful` solution for grails 
- [x] create basic restful `GET /users.json` action
- [x] icons for pager are missing
- [x] `okIcon` formatter is missing
- [x] fix ordering by contact fields
- [x] re-implement quick filter
- [x] re-implement the form
- [x] re-implement create action `POST /users.json`
- [x] re-implement update action `PUT /users/:id.json`
- [x] add AngularJS validation to the create/update user form
- [ ] handle server-side errors
- [ ] create solution for flash messages
- [ ] re-implement complex search
- [ ] re-implement delete action 'DELETE /users/:id.json`