Widgets: Add some list items.
Pages: Added a Page for setting photo locations.
Settings: Save settings when backup loaded.

When the SettingsManager has to load a backup it should save the
settings again.
Settings: Add Photo Locations to defaults.
Models: Add Setter and Listing models.
Page: Bug reminder.
FileSelector: Make signal names consistent.
Glue: Add Glue for the FileSelector View.
Views: Add a List View.
Pages: Move the close program to the Page base.
Pages: Add a Photo Locations page.
Page: Add a bug reminder.
Thread: Functions to check current thread/process.

Checks whether the current thread or process is the main thread or
process. Useful for checking when a function should only be run in
certain circumstances.
Photo DB: Check for new or deleted files on init.