Replace the 'view' and 'view all' add_to_log calls with events

Signed-off-by: Tony Butler <tonyjbutler@gmail.com>
report_outline: Update report to use logging API

Signed-off-by: Tony Butler <tonyjbutler@gmail.com>
Update README.txt for Moodle 2.7

Signed-off-by: Tony Butler <tonyjbutler@gmail.com>
Bump version number and require Moodle 2.7 release

Signed-off-by: Tony Butler <tonyjbutler@gmail.com>