fixing the "when admin creates alias and unticks the checkbox don't overwrite it on subsequent edits" bug

Here's the list of bugs that need to be fixed to get that working:

0 Since I reverted the code so far and stuck it in 180440 that would probably go in first and then...
1 http://drupal.org/node/193825 - maintenance for url_alias_extra
2 http://drupal.org/node/206461 - delete from url_alias_extra as well as creating the entries
3 http://drupal.org/node/201659 - which mostly works, but needs some more work in 193825

I think that's it. Each of those may involve multiple pieces of work, but at least between the original issue and the comments that should cover it.

I add this becase neclimdul asked about it.