[Model] Ensure knowledge base integrity

[luis100]

• Check index integrity on startup
• Support information backup
• Check if probability of index corruption can be reduced by TDB.sync()
• Check if index can be recovered

[luis100]

TDB has one major disadvantage - lack of data integrity. If the application is restarted in the middle of transaction - the TDB backend doesn't recover well. Extra steps must be taken to ensure data integrity while using this backend.

http://svn.eionet.europa.eu/projects/Reportnet/wiki/JenaFrameworkEvaluation