PIM-3319: Added value check for filters and specs
PIM-3319: Fix exceptions and specs + refactor some code
PIM-3319: Fixed some typos in the use of exceptions
PIM-3319: removed unused methods
PIM-3319: Update the changelog
PIM-3319: Fix behats and specs
Merge pull request #1803 from akeneo/PIM-3319

PIM-3319: Added value check for filters and specs