Including in this commit:
- Moved the backup controller instantiation out of the constructor
- Created a new get_backup_controller() method to retreive the controller when needed
- Removed some constructor-promoted properties
- Added resourcefilename to resource_packager constructor
- Made resource_packager to abstract class (cannot be instantiated)
- Removed constructor-promoted properties and declare them "normally"
- Backup controller is called and destroyed in get_package() method.
Only PHPUnit tests will need to play with the destroy method because
they use the reflection method
- Made course_partial_packager extend course_packager and removed constructor-promoted properties
- Removed the get_all_task_settings() method and replaced it with get_all_activity_tasks() method
- Fixed bugs related to Partial course sharing
Eloy Lafuente (stronk7)