WIP
- Add Coupon Event
- Customer Parameter
Merge branch 'coupon' of https://github.com/thelia/thelia into coupon

# By Michaël ESPECHE
# Via Michaël ESPECHE
* 'coupon' of https://github.com/thelia/thelia:
  WIP
  Working
  WIP
WIP
- Update Coupon Controller/Form/Event - create()
- Rule serialization/unserialization managed in Model/Coupon now
Merge remote-tracking branch 'origin/coupon' into coupon