Merge pull request #7 from MicaelRodrigues/master

Inconsistencies in the *_users_to_group functions and description
Assigned ->course with ->courseid instead of ->id for the case when ws_is_enrolled evaluates to false
Merge remote-tracking branch 'upstream/master'
Replaced deprecated  get_context_..... functions, that will be deprecated in Moodle 2.8, with context_xxxx::