LDEV-3599: Load only first few learners for each activity and lesson completed. Count learners for each activity, including hidden children of Branching in Flash format. Fetch full learner list on demand.
Remove unnecessary methods.
Load the really needed objects instead of using Hibernate to derive them from parent objects. Use SQL for counting instead of fetching full collection in Hibernate and checking its size.
Prepare for paging: add offset parameter to queries.
