Make it possible to select which channels can make the minimized chat window blink.

Help and general chat channel are fun to be in and very active, but they are not as important as the Beta-island intel channel. When my chat window is minimized and it starts to blink. It could be because someone is reporting an invasion of foes coming my way, or because someone asked what button to click to leave the terminal. Only one of these situations is worth having a flashy icon.