Update documentation

```
Update installation documentation to point to joshmarshall's new tornadorpc 
repository on github (https://github.com/joshmarshall/tornadorpc), and that one 
can get tornado and jsonrpclib from pypi now.

```

Original issue reported on code.google.com by `andrew.f...@gmail.com` on 14 Jun 2011 at 11:50
