PIM-1603: Remove translation foreign key from entity
PIM-1603: Update CHANGELOG file
Merge branch 'master' into PIM-1603

Conflicts:
	CHANGELOG.md
PIM-1603: Allow to add empty translation
PIM-1603: Clean AbstractTranslation class
Merge pull request #591 from akeneo/PIM-1603

[WIP] PIM-1603: Impossible to remove an entity translation