Now that the item price is stored in Order as well, we no longer need to store the index into the Item model there. Remove that code.
Added basic database code and items database implementation. Thanks xtg in the Gopher Academy Slack and Company in irc.gimp.net/#gtk+.
Hooked up the database save/load to the item editor and removed the sample items now that the items are loaded from a database.
More TODOs.