Fixed Doctrine event method call

See #28

Command changes its name

The command should now be invoked with container:listeners-debug

Tests and bugs

• Elevated coverage to 100%
• Fixed bug related to subscribers that was introduced after the refactor to a library

ListenersDebug as a library

All the logic with regard to the logic of collecting, filtering and ordering has been delegated to the ListenersDebug Library to allow to be used in projects that don't use Symfony but their components

Support for multible subscribers per event

Thanks to @digitalkaoz

Fixed bug regarding subscribers

Merge pull request #13 from lolautruche/subscriberSeveralEventsWithPr…

…iority

Fixed crash with TableHelper when an event subscriber definition is an array of arrays