added changes for monitoring to gate activities (gate_open, gate_start_date_time, gate_end_date_time), plus changed lesson_copy_flag to copy_type_id and added lams_copy_type table, added help_text to lams_activity table, added supports_moderation_flag and contribute_url lams_tool table
add some domain convenient methods, such as getAllLearners for a lesson, validate the type of an acitivity. change cascade to save-update between learningdesign and activity.