Switch back to current codeparty master.

Updates the packages.json, switching to depend on codeparty derby and racer, as per:

https://github.com/codeparty/derby/wiki/Using-Derby-%22Edge%22

albeit at the most recent commit on 20130110-0830. Tested that `make run` results in a server with the expected functionality using Chromium 22.0.1229.94 Ubuntu 12.10 (161065).