[WIP] Resurrection 

## The Godmin Cleanup Initiative

- [x] More robust template overriding that covers all the scenarios
- [x] Isolate admin code within an engine that in turn uses godmin
- [x] Simplify default scope + make sure it is always defined
- [x] Simplify batch processing
- [x] Preserve ordering when filtering and clearing filters
- [x] Defaults for permitted params
- [x] Defaults for navigation menu
- [x] Internationalization (https://github.com/varvet/godmin/pull/6)
- [ ] Authorization / Authentication (https://github.com/varvet/godmin/pull/7)
- [x] Better breadcrumbs
- [x] Form errors
- [x] Pagination
- [x] Remove support for magic scopes
- [x] Rename batch processes -> batch actions everywhere
- [x] Rename scopes and filters macro methods -> scope and filter
- [ ] Create a default dashboard_controller#index action and add root_path
- [ ] Provide a generator for setting up godmin
- [ ] Some documentation would be nice
- [ ] Tag godmin prior to merge so existing apps wont explode 

Other issues:
- Should helpers be namespaced or not?
Line is too long. [201/120]