PIM-1401 Fixed displayed conversion unit fields for a given channel

In fact, one field should be displayed for each metric attributes (and
not one field per metric family). This allows to define two different
conversion units for two metric attributes that are using the same
metric family.
Merge branch 'master' into feature/pim-1401
Add behat scenarios for editing import/export configuration
Fix translation
Update scenario
Fix multi-step job configuration
Added metric values in demo fixtures
PIM-1401 Fixed typo
Merge pull request #550 from akeneo/PIM-1638

Fix multi-step job configuration
Fixed convert metric feature description
Update oro ref
Merge pull request #548 from akeneo/feature/pim-1401

PIM-1401 Fixed displayed conversion unit fields for a given channel
Merge branch 'master' into PIM-1641

Conflicts:
	composer.lock
	src/Pim/Bundle/DemoBundle/Resources/config/installer/demo_dev/attributes.yml
	src/Pim/Bundle/DemoBundle/Resources/config/installer/demo_dev/products.yml