Comment 9 for bug 208611

Seems the correct way to do this is as follows:

1) Have a default directory to store notebooks, e.g. ~/Notes
  - so my notebook 'agenda' would be below ~/Notes/agenda by default
  - on windows the default should probably be called "~/My Notes" ...
2) Make this directory configurable through the xdg-user-dirs system
  - so setting a environment variable like XDG_NOTES_DIR can change this default
  - this gives users and sys admins freedom to choose a different layout
3) Use the XDG_DOCUMENTS_DIR as default document root
 - so /foo.pdf will link to e.g. ~/Documents/foo.pdf (or ~/My Documents/foo.pdf on windows)
 - this is consistent with where other desktop programs will look for user documents
 - documents in other directories can be referenced with "file://" urls and ~/.. will also work as expected
4) Consistently talk about "attachments" if documents are incorporated in the notebook directory
5) Allow specific data dirs to be incorporated (e.g. templates)
  - Would be security issue to have all data dirs incorporated
6) In the "open notebook" dialog automatically show all notebooks in the notes dir as well as allow extra paths to be added
  - like default directory listing + bookmarks