Pin IPython version to 2.x
Pin IPython version to 2.x

New version of IPython breaks all of our notebooks.

menpo/menpo,menpo/menpo,yuxiang-zhou/menpo,patricksnape/menpo,yuxiang-zhou/menpo,grigorisg9gr/menpo,mozata/menpo,mozata/menpo,menpo/menpo,grigorisg9gr/menpo,patricksnape/menpo,grigorisg9gr/menpo,mozata/menpo,yuxiang-zhou/menpo,mozata/menpo,patricksnape/menpo