Increase Luminosity of Usernames

Function adapted from http://www.sitepoint.com/javascript-generate-lighter-darker-color/ , I presume that 50% lighter is a good starting point ( the 0.5 in https://github.com/VxJasonxV/avalonstar-live/blob/5c1dffeed145be2d42f317bf6e07b5106a12466e/app/models/message.coffee#L27 ), but it definitely needs to be evaluated, and I have no idea what the best way to accomplish that is.

coffeelint isn't complaining, but that doesn't mean much.