Add capability "addinstance" as required by Moodle 2.4+
Fix MySQL-specific quoting
Explicitly create this->config to avoid warning message
Create this->content explicitly to avoid warning message
Add myaddinstance capability as now required by Moodle
Use ->sql_concat rather than MySQL-specific CONCAT()
Merge pull request #13 from MorrisR2/update_for_moodle_27

Update for moodle 27