Group operations now expose the idnumber parameter present in Moodle 2.3+.

Groups gained an 'idnumber' attribute in Moodle 2.3 as a result of MDL-32005:
https://tracker.moodle.org/browse/MDL-32005
This 'advanced' attribute can be used to map groups to external data sources.
Grouping operations now expose the idnumber parameter present in Moodle 2.3+.

Groupings gained an 'idnumber' attribute in Moodle 2.3 as a result of MDL-32005:
https://tracker.moodle.org/browse/MDL-32005
This 'advanced' attribute can be used to map groupings to external data sources.
Merge pull request #6 from adamfranco/Group_idnumber_support

Expose Group and Grouping idnumber attributes

@adam thanks for warning me. I pressed the wrong button on github. It should be ok by now

Cheers