[BT] TorrentFilesModelBase::FindIndex().
[Util] ModelItemBase::AppendExisting().
[BT] TorrentNodeInfoBase::Reparent() for #1736.
[BT] Support announcing rows on parent creation for #1736.
[BT] Just ignore missing names on update.
[BT] TorrentFilesModel::handleFileRenamed() for #1736.
[BT] Handle file renamed alerts for #1736.
[BT] Update size graph on renames.

This finally closes #1736.