Better spec coverage + fixes

- Fix so specs pass.
- Add more specs now 95%+
- Fix all locales and removed duplicate sub locales (tested with
i18n_spec).
- Add Swedish locale.
- Moved generator.rb to sub "install” dir because it didn’t init.
- Fix assets paths.
- Admin pages tab moved to Configuration due to it made top menu
items collapse, new layout same style as products for consistency.
- Fixed hooks etc to correspond to Spree 2.1+ way.