PIM-3558 : update the flat value normalizer to order attribute options
for multiselect
Merge pull request #1927 from akeneo/PIM-3558-order-of-options

[SLA] PIM-3558 : update the flat value normalizer to order attribute options
Preparing version 1.2.18
Merge branch 'master' into merge_118

Conflicts:
	CHANGELOG.md
	src/Pim/Bundle/CatalogBundle/Version.php
PIM-3558 : re-work the fix to use interfaces and not abstract classes
Merge pull request #1931 from akeneo/merge_118

Merge fixes from v1.18