[WIP] Loading fixtures with Nelmio/Alice

The goal is to be more flexible, to be able to load a bigger and more random catalogue.

- [ ] install Nelmio/Alice
- [ ] install hautelook/AliceBundle
- [x] countries
- [x] exchange rates
- [x] promotions
- [x] users
- [x] product properties
- [x] zones
- [x] product options
- [x] taxation
- [x] shipping
- [x] payment methods
- [ ] images 
- [x] taxonomies 
- [ ] products
- [ ] orders