Pull request for socolissimo 2.8.0

Socolissimo 2.8 :

- API socolissimo 4.0
- Add seller unique cost for seller delivery
- Add delivery in Belgium
- Add so mobile device for smartphone(use API 3.0)
- New Params in Back office
- Fix various from previous versions :
- Gift message now working
- OPC now working for both 1.4 and 1.5
- Api key calcul now working properly
- encoding character in adress or gift message now properly working

- Module must be unistall and reinstall due to datebase changes.(country
is now mandatory)