Instead there is a new type called 'UnopenedFile'. This was part of my
effort to not have everything inside the 'Note' class and to make it a
bit more immutable.
But, wow, this took a very long time. The 'Note' class seems to be very
deeply integrated everywhere.
Also simplify the loading logic. This makes it much easier to
understand.
With this, I can now slowly migrate the interface of a NotesFolder to be
based on Files instead of Notes.
I'm trying to expand GitJournal and let it understand the concept of
different Files. Right now everything is mashed into the "Note" class,
which is messy.
