Multiple windows mode

• Multiple windows interface (option in menu)
• Clickable magnet links
• Multiple a/v calls simultaneously
• Contact group collapsing
• toxme.io https api (resolving names)
• Auto send greeting message on contact online (see contact properties)
• Fix message create time of delayed messages
• Fix contacts sorting
• Fix tox group chats
• Fix maximized window (don't block auto-hide taskbar)