Unescape urls returned by filechooser

Reduce code duplication between session and request

Introduce a changelog file

Make appearance namespace const public

settings: Correctly unwrap the changed value

settings: Let ReadOne fall back to Read on error

Fall back to old Gnome prefer-dark if first try fails

Merge pull request #11 from quexten/feature/notification-icon-optional

Fix possible crash for unexpected response

Get SaveFiles working and input API coverage to 100%