#56 Database improvements

This adds two improvements to the statistics database.

• Code was added to use SQLite's user_version field to specify database versions. When the database is outdated, ID2T automatically regenerates the database. This depends on the developers manually changing DB_VERSION in statistics_db.h whenever the structure of the database or the meaning of fields in the database changes.
• I added a byteCount field to ip_protocol and ip_ports. I implemented it like issue #7 suggested, so the fields contain the number of bytes instead of kbytes like ip_statistics. Let me know if you'd prefer kbytes.

This is a great change. Could you please add this information to the WIKI as well?