Call it DEV version on the master branch
Expand the referenced course section by default
Do not use deprecated make_categories_list()
Bump required version
Remove deprecated get_context_instance call
Call it 2.6.0
Fix the legacy plugin meta-info declaration
Bump version and call it 2.7.0
Migrate legacy add_to_log() to the new event API

Based on the original Vadim's patch with some fixes and clean-ups.
Replace the legacy cron function with a new scheduled task
Update README and LICENSE files
Automated grades fetching with event observers