Improve PromotionRepository

1/ Fix the date conditions (the old ones weren't retrieving anything on null dates)
2/ Add some join to avoid recurent queries
Automatically set promotion amount as discount
Fix CS
Merge pull request #3 from winzou/patch-2

Automatically set promotion amount as discount
Merge pull request #2 from winzou/patch-1

Improve PromotionRepository
Prototype of making bundle subject agnostic
Use separate flag for coupon based promotions
Check for coupon validity when transforming, fix money fields
Fix coupon to code transformer
Implement initial coupon generator
Dutch translations
Init polish translation
Cleanup of code.
* Fix phpdocs,
* Fix interfaces that blocked extending,
* Reuse new ResourceBundle interfaces,
* Fix fatal errors.
use strict in js
Merge pull request #6 from tvlooy/dutch_translations

Dutch translations
Merge pull request #7 from Antek88/master

Init polish translation
Merge pull request #4 from stloyd/feature/interfaces

Cleanup of code.
Fix translations
 Converted translations to xliff format
Merge pull request #8 from umpirsky/feature/translation-yml-xliff

 Converted translations to xliff format