On destroy() the window that was last focused gets the focus
again. if destroy() is called from the StartChat Dialog, the new
ChatControl is not yet focused, because present() seems to be asynchron,
at least on KDE, and takes time.
- Move ActionBar into HeaderMenu
- Make Design of ChatControl look cleaner
- Hide the Roster in Groupchats per default
- Add Button to hide/show Roster in Groupchats
- Move Groupchat topic into popover
- Display Avatars on the right side of the ChatControl and status on the
left
- Add a default Avatar for contacts that have none