[Util] Added FlatToFoldersProxyModel::FindFolder() for #1421.
[Util] Code style fixes.
[Util] Fixed FlatToFoldersProxyModel::MapFromSource() for #1421.
[Aggregator] Select proper channel on thru-pass.

Closes #1421.
[Azoth] Core::GetUnreadCount() for #1420.
[Azoth] ReformatTitle() now public and returns the title.

For #1420.
[Azoth] Initialize unread msg count properly for #1420.
[Azoth] Emit the tab with the proper title.

Finally fixes #1420.