ipython/ipython — pull request #2378 by minrk (2012-09-04 00:21:31+00:00)
Title: use Singleton.instance() for embed() instead of manual global

Any use of get_ipython() could cause funky misbehaving,
potentially invoking another InteractiveShell instance.

One change is calling IPython.embed() from inside a running IPython session will now result in a MultipleInstanceError.

closes #1884