Change tab and window icon when someone is typing or there is unread message

Tabs will have 'unread-message' icon when there is an unread message.
When there are no unread messages, but other side is typing, it shows
a 'typing' icon. Otherwise contact's presence icon is used.

The window will have 'unread-message' icon when there is an unread message
in any tab. Otherwise will show 'typing' if user in current tab is typing.
Otherwise it shows current tab presence icon.

REVIEW: 108500

FIXED-IN: 0.6