moduledata task now using API class to get programmes

Also fixed a bug getting the correct pos_code value out and in the programme index data
Merge branch 'feature/module-data' of github.com:unikent/programmes-plant into feature/extend-api-capabilitys
Merge branch 'feature/extend-api-capabilitys' of https://github.com/unikent/programmes-plant into feature/module-data
updated composer.json to point at unikent programmes-plant-modules repo
Merge branch 'feature/module-data' of github.com:unikent/programmes-plant into feature/extend-api-capabilitys
Assert ownership of revisions via get_revision method.
Update tests to check new feature & work with it.
handle no related courses better.
Update composer.