update -dev docs to reflect latest stable version

also updated the release codename, so it doesn't stay with the old "An 
Afternoon Hack" one.

After this is merged, it'd be good to build the docs and push them to 
http://ipython.org/ipython-doc/dev/ - and I don't believe I have the 
permission to do that, but @minrk and @takluyver probably do.