Qt somehow handles scrolling on new messages on its own when the
ListView direction is bottom to top.
In normal top to bottom, manual scrolling is completly buggy.
Replace the "reloadThis" ListModel hack by an actual signal,
works when the subtitle is displayed in more than one place
(e.g. two accounts in the same room connected).
- Fix roomList height again, now based on model.count().
All delegates are assumed to be the same height
- Properly update room list when a room is joined or left
- Catch exceptions happening in threads (futures), which previously
passed silently
- Show "Empty room?" as "<i>Empty Room</i>" + gray [?] avatar
To make the models update correctly in QML:
- ListModel and _QtModel merged
- Return a ListModelMap QObject from properties instead of
a DefaultDict → QVariantMap
