Create VariantImageInterface.php
Adapt VariantInterface

Delete VariantImage entity dependency (this is a model!)
Decouple Variant and VariantImage entities
Make VariantImage entity implements VariantImageInterface
Fix PHP Doc
Merge pull request #56 from winzou/patch-1

Decouple Variant and VariantImage entities
Merge branch 'master' of github.com:Sylius/Sylius
improve some views
add translation to backend tables