Create a daily build PPA for ipython

[ipython]

Original Launchpad bug 417969: https://bugs.launchpad.net/ipython/+bug/417969
Reported by: fdo.perez (Fernando Perez).

Once our trunk stabilizes some, we should offer a daily PPA to make it easy for interested users to follow our tree.

Some useful links and references:

https://code.edge.launchpad.net/~fta/+junk/ppa-confs
https://code.edge.launchpad.net/~fta/+junk/ppa-scripts
https://wiki.ubuntu.com/DailyBuilds
http://castrojo.wordpress.com/2009/08/21/making-daily-builds/

[fperez]

Github offers pretty good archiving facilities, and I'm not going to do any further work on Launchpad. Closing from our side, we can always publicize a third-party PPA if a maintainer offers one on the list.