Patch: As a dev, I would like some hooks added to this module, and a way to force repeating_date_has_changed.

THis simple patch:

1. Adds 2 drupal_alter hooks:
   • hook_date_repeat_entity_entity_presave_before_alter <-- act before date_repeat_entity does its presave thing.
   • hook_date_repeat_entity_entity_presave_after_alter <-- act after date_repeat_entity has done its presave thing.
2. Adds a condition to date_repeat_entity_repeating_date_has_changed allowing me to force a TRUE or FALSE response by adding $updated_entity->repeating_date_has_changed = TRUE/FALSE to the $entity before saving