Nondeterministic behaviour

[karlicoss]

Steps to reproduce:

1. open emtry file (e.g. issues.org) and org-sync-import some repository, e.g. https://github.com/arbox/org-sync-test; save he file
2. [optional] add issues.org under version control so it's easier to reproduce the bug
3. run org-sync and save the file.

What happens: issues get randomly reorderd (you can see it in git diff)

What's expected: if there were no changes, file should stay exactly same

I'd bet that it's one of the hash tables here to blame :) I'll try to look into that later.