Behat scenarios
Behat tests : filling scenarios and splitting tests to avoid side effects during promotions calculations
Behat tests : adding scenarios to handle fixed and percentage discounts, cleaning promotion configuration that is serialized in database.
PromotionBundle : fixing bug on non existent "equal" configuration
PromotionBundle : fixing bug (usage limit was not checked)
Rendering percentage discount ONLY on the items total (on not the whole order total)