A global settings button system #186
Description
Every window should be able to add a settings button to the top right.
Clicking the button should pop up a list of settings related to that window.
We need to find a way to fit a large amount of settings in this pop up, perhaps through the use of tabs, or maybe make collapsable sections.
The user should be able to specify where a setting is stored (see the list at #260). The content window should provide a sensible default location for the preference, which might differ for each preference.
The content window can also limit the locations where a preference may be stored.