Remove inversedBy relation between Attribute and AttributeValue

Fix issue #1480 and #1372
Adding some minor adjustments
Fixed multiple sorting in Doctrine ORM EntityRepository

QueryBuilder's orderBy method replaces any previously specified orderings, addOrderBy must be used to append more than one.
Merge pull request #1843 from hmlb/patch-1

Fixed multiple sorting in Doctrine ORM EntityRepository
Fix 1834
Typo in specs
Merge pull request #1848 from umpirsky/fix/typo-23-08-2014

Typo in specs
Merge pull request #1847 from aRn0D/fix/1834

Fix 1834
Merge pull request #1482 from BenoitLeveque/fix-doctrine-mapping-on-attribute-value

Add missing relation between Attribute and AttributeValue
Merge pull request #1839 from aRn0D/bundle/config

Adding some minor adjustments