allow keyboard interrupt to break out of ipdb @takluyver @minrk and I discussed this issue in person. It's currently problematic that there is no way, short of restarting a kernel, to get out of an ipdb session if you've deleted the output of the cell in the notebook which started it (by e.g. re-executing that cell). This patch makes Ctrl-C behave the same as Ctrl-D inside of ipdb - it exits the ipdb session. This also makes it possible to stop ipdb sessions from another client. I polled @katyhuff, @scopatz, and some other pyne/pyne hackers and they were surprised to hear that this was not the behavior already.