use base lifecycle event
Depend on doctrine/common 2.4.x and related libs
Refactor event classes to extend common base classes

OnClearEventArgs and ManagerEventArgs can extend their common base classes.

preLoad is a lifecycle event, so PreLoadEventArgs should extend LifecycleEventArgs.
Fix RST title syntax
Revise "Migrating Schemas" documentation
Reintroduce HasLifecycleCallbacks annotation
AnnotationDriver should ignore inherited methods

Only consider methods declared in the current class being processed. This is consistent with ORM's AnnotationDriver.

See: https://github.com/doctrine/doctrine2/commit/67ae22b9118cd5bbd8a897b76ac68ffca263c4e2
Document reintroduced HasLifecycleCallbacks documentation

This documentation was originally removed in abcf27564c3ed18f6fa6b8084d75e393cb30ca5c, after the annotation itself was removed in e9af24994055f94aede98593e7c2c421ee6a0a22.
Improve AlsoLoad annotation documentation

Discuss how AlsoLoad may be used for methods, and link to migrations page.