DB upgrade

The SCORM 2004 introduce sequencing with a complex definition in the manifest and this causes a lot of new needed for store all the things in the DB.
Moreover to have a more flexible scoes attributes storing, every SCORM/AICC type has some different attributes, the scorm_scoes table must be changed and an attribute table is needed so the global sco informations are stored in the classic scorm_scoes table and all the type variable attributes will be stored in a new table.
Attached you will find an idea of MySQL table definition I think is needed, please check if it's the right idea.
All the related files (XMLDB, other DBs, backup and restore) must be updated and several part in the library code needs to be changed.