Adding a few db statements - sync_status
Fixing pointer notation
Adding GComprisLog struct declaration

This is to make it easier to return GCompris log data.
Converting returned data set to list of logs

completing the db method get_logs_data
Fixing all the build errors

Cleaning up typos and stupid mistakes
Avoid fetching class_id in the user_list

To avoid class_id being null resulting in an error, just
avoid fetching it in the first place. We anyways don't need
it.
Finishing integrating UserService

Rough and still need to cleanup (move url to settings for e.g.)
but basic flow works as designed!