Added shipping
Merge pull request #2 from umpirsky/shipping

Added shipping
Add zones to taxes and shipping, refactor data fixtures
Add assortment bundle as dependency
Add initial Product and Variant entities

* Add doctrine mapping for those entities.
* Add basic forms.
* Add simple price for Product.
Add product short description
Inherit price from master variant
Make product taxable
Update tax category choice type name
Update zone choice type name