Merge pull request #97 from norzechowicz/refactoring

Refactoring
Added tests on specific symfony2 versions
Updated dev dependencies
Merge pull request #98 from norzechowicz/travis

Added tests on specific symfony2 versions
Update events.md
Removed hhvm env from travis
Merge pull request #99 from norzechowicz/travis

Removed hhvm env from travis
Moved classes related with Doctrine to Doctrine namespace