Better onsite alerts

We've put in a new system to show better onsite notifications and errors.  We used to show them as color bars in the bottom of the browser window, but people commented they didn't always notice them. Now you'll see them in the top right of your browser window. These notifications alert you to successful actions like completing a trade:

or warnings that something didn't go quite right, like an unsuccessful login:

We hope they'll be easier for people to spot and at the same time not be intrusive. They were of course inspired by the wonderful Growl notifications software for the Mac and were made possible by Stan Lemon's excellent jGrowl library, a javascript implementation of Growl.