Merge branch 'PIM-3475' into PIM-3475-merge

Conflicts:
	features/export/export_options.feature
	spec/Pim/Bundle/TransformBundle/Normalizer/Flat/AttributeOptionNormalizerSpec.php
	spec/Pim/Bundle/TransformBundle/Normalizer/Structured/AttributeOptionNormalizerSpec.php
	src/Pim/Bundle/InstallerBundle/Resources/fixtures/icecat_demo/attribute_options.yml
	src/Pim/Bundle/InstallerBundle/Resources/fixtures/icecat_demo_dev/attribute_options.yml
	src/Pim/Bundle/TransformBundle/Normalizer/Structured/AttributeOptionNormalizer.php