- Avatar disabling was not correctly handled for all cases, this should now be fixed.
- Avatar retrieval is now down only on PEP events, no directly anymore. `get_avatar` only
returns cached version.
`NS_AVATAR_METADATA` is already advertised by `add_pep_event`, adding it to `getDiscoInfo`
too was resulting in double advertising, making the disco infos invalid for caching
(resulting in other devices repeatedly requesting disco#info).