Simplified order.c's GUI code.
Restructured the database code in some major ways: I have a better idea of what the transparent framework should look like, there's one less call to itemsModel(), and saveItems() is in items.c.
Changed database input to work similarly to output (see previous commit).
Simplified the code for the PayDialog quite a bit.
Simplified the Shift GUI code.
Simplified the Log In screen GUI code and added a Settings button to its header bar.
Split the Login window and accounts stuff; the accounts stuff (including Account Editor) is now in accounts.c.
Split the items model setting from the items column layout setting and restructured related code.
Removed itemsModel() at last by moving the create filtered items model code there instead (renaming the function).
More TODOs.
Renamed Settings on the Login screen to Manage.