#1159 - base coverage for the `Doctrine\ORM\Repository\DefaultRepositoryFactory` implementation
#1159 - verifying that `Doctrine\ORM\Repository\DefaultRepositoryFactory` caches instantiated repositories locally
#1159 - verifying that `Doctrine\ORM\Repository\DefaultRepositoryFactory` considers custom repository class from metadata when instantiating repositories
#1159 - `Doctrine\ORM\Repository\DefaultRepositoryFactory` should create different repositories for different entity managers
#1159 - optimized imports
#1159 - `Doctrine\ORM\Repository\DefaultRepositoryFactory` keeps separate caches per entity manager used to build repositories
#1159 - protecting `Doctrine\ORM\Repository\DefaultRepositoryFactory` API by making it `final` and its `protected` members `private`
#1159 - adding `UPGRADE.md` notes for `Doctrine\ORM\Repository\DefaultRepositoryFactory` becoming `final`
#1159 - EOF EOL CS fixes for `Doctrine\ORM\Repository\DefaultRepositoryFactory` tests
Merge pull request #1160 from Ocramius/hotfix/#1159-multiple-entity-managers-per-repository-factory

#1159 - multiple entity managers per repository factory should be supported