Chat window: improve tab display

[ge0rg]

When you have very many open tabs, many of them degenerate into "... [X]" or "(... [X]":

I'm not sure why some tabs get more space than others (conversations got the full unread-number plus six letters, while swift only got a (), but this looks strange.

It would be great to follow the UI of recent Firefox/Chrome, which removes the close symbol earlier, and leaves the page favicon as the last visible entity:

Please do the following:

• make all tabs equally wide
• hide the 'X' close button when the tab width goes below some threshold
• add avatars to the beginning of the tab if possible