v2.2.0

• Bump minimum version to PHP v5.4.0.
• Add Orchestra\Memory\ContainerTrait.
• Deprecate Orchestra\Memory\Abstractable\Container.
• Replace array_set() with array_add() when loading value from storage.
• Allow to get handler instance using Orchestra\Memory\Provider::getHandler().
• Add Orchestra\Memory\Abstractable\Handler::getStorageName() and Orchestra\Memory\Abstractable\Handler::getName() helper method.
• Tweak the way Orchestra\Memory\Abstractable\Handler::isNewKey() is detected.
• Improve type checking for Orchestra\Memory\Abstractable\Container::attached() and fixes docblock.
• Avoid generating checksum from running serialize() on an already serialized string.
• Avoid using continue in foreach.