PIM-2288: First implementation of mass action dispatcher
PIM-2288: Add phpdoc and remove useless event
PIM-2288: Rename event
PIM-2288: Clean MassActionDispatcher with event dispatcher
PIM-2288: Add php doc on MassActionEvent
PIM-2288: Update CHANGELOG.md
PIM-2288: Remove useless code
PIM-2288: Change mass action event definition
PIM-2288: Inject datagrid instead of datasource
PIM-2288: Refactoring mass action dispatcher
PIM-2288: Add mass action interface to mass action event
PIM-2288: Clean methods
Merge pull request #931 from akeneo/PIM-2288

PIM-2288: Dispatch event after handler call