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
Allow instant redirect to the referenced course

Based on the idea by Matt Gibson who did this in his fork. This does not affect
users with the permission to fetch grades manually so they do not loose this
option.
Describe recent changes in the README file
Fix missing capability names
Check for the permission before fetching grades on activity update

In a rare case when the teacher does not have permission to fetch grades
manually, do not fetch grades on the subcourse activity update.