Export2odt: Make list-, details- and note-styles be kids of node-style.

This includes:
* For each style in the map, create depending style with the same name,
  just " Note" resp. " Details" appended.
* For each style in the map and their" Note" and "Details" styles,
  create additional automatic styles for the lists.
Add documentation for last change.
Update .gitignore.