[addons] don't group add-ons into categories in disabled and available update sections of the add-on maanger
[addons] allow GetAllOutdatedAddons to return the local addon versions - useful for scheduling updates
[busydialog] factor out the dvdplayer busy dialog waiting so as to use it for other things
[addons] add 'Update all' item to the available updates menu
[addons] notifying the user once during repo updates is enough
Merge pull request #4260 from jmarshallnz/addon_improvements

Addon improvements