Google Code-in

When addressing someone in a chat room, its common to include their name followed by a colon so that they know you're speaking to them. Most chat clients will play a sound and/or highlight the message so that in a busy chat room its easier to carry multiple conversations at the same time.

Implement this in our webchat by scanning for the user's own nickname followed by a colon. If found, follow the same sound behavior as private messages (which can be turned on/off with the same button) and highlight the sender's name on the left of the message with bold text and a different background color.

If possible, add this code to commands.js and attach the changed file to this task. If that is not possible, explain why in a comment and attach your work by another reasonable means (eg, a diff).