Currently we only need the db to keep track of the files that were
already downloaded, thus we only use one database and only one table.
A complete sql database is a bit too bulky for this purpose.
By using sqlite we can minimize and embed the db.
- mysql creates database and tables to given mysql if not existent already
- mysql reads last change values from db
- mysql saves ch_date after downloading
- run now takes care for the variables of mysql and studip