Adding ein2 project

A fork of tkf's ein project (https://github.com/tkf/emacs-ipython-notebook), which appears to have become abandonware. EIN2 aims to provide support for IPython notebook versions 2.0 and
beyond. Somewhat relevant discussion in tkf/emacs-ipython-notebook#155 and tkf/emacs-ipython-notebook#156.

Project page is https://github.com/millejoh/emacs-ipython-notebook and I
am the current maintainer of the project.