It is being kept up for posterity but the code is actually quite poor (it all works). I have noticed a few people forking it but please do not (although by all means make use of the code if you'd like to).
There are a variety of better alternatives:
The agent base model is in fact not quite yet re written but this is an ongoing piece of work by an MSc student. The repository will be here where the library will be packaged properly.
Another package that might be of interest is this Axelrod library which allows you to reproduce the Axelrod tournament.