Merge pull request #982 from akeneo/fix/attribute_option

Added constraint on attributeOption
Remove cascading between Product and Family
Simplify LocaleController and remove unused locale routes
Simplify the MediaController
Remove sending error by email by default on prod env
Add a note on Reader and Writer changes
Prepare the 1.2-dev
PIM-1964 Group datagrid attribute filters by attribute group
Update FiltersConfiguratorSpec
Merge branch 'master' into PIM-1964
Update changelog
Merge branch 'master' into controller_fixes
Add a property to choice attributes to define whether options are sorted automatically
Merge pull request #1026 from akeneo/controller_fixes

Avoid extending the AbstractDoctrineController when not necessary
Merge pull request #1027 from akeneo/PIM-1964

PIM-1964 Group datagrid filters
Fix custom property initialization in attribute form and remove manual rendering
Update typo in CHANGELOG.md
Fix js issue with displaying system filter group when another group has a sortOrder of 0
Fix method complexity and variable length
Merge branch 'master' into PIM-1702