MDL-58334 and MDL-32471 introduced new parameters in pluginfile.php but
they are missing from webservice/pluginfile.php
We need the offline one in the Mobile app (this new parameter was
designed thinking in the mobile app)
dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
1. Implement core_course_get_contents web service
2. Implement callbacks in folder, resource, page and url modules
3. Implement download script for web service