upgrade to newest cismet-commons version2
[issue #12] replaced getClassPermission by getPermission template operation
[issue #11] added copy operation for usergroups
[issue #10] added getter for the backend to persistence provider
Merge branch 'feature/12-permissions-per-usergroup' into dev
Merge branch 'feature/11-copy-usergroup' into dev
Merge branch 'feature/10-backend-from-persistenceprovider' into dev