Stop it being a singleton. This means it needs to be passed around a
lot. This sucks, but it's how it should be. I shouldn't be using a
global variable to get around this.
This is needed as Settings will soon become repo specific when we
support multiple repos.
This breaks saving the settings in a file, that feature was toggled off
anyway. It needs to be thought over again.
It doesn't make any difference as -
1. The sort order shown our SortedNotesFolder is different
2. Rebuilds of the tree affect everything. Even the elements which
should be in the correct place.
This is just for optimizing the loading of the Notes in the correct
order. I want to avoid the notes appearing and disappearing in a strange
order when loading. It gives a bad first impression.
This cache isn't integrated, it's only half done.
