Revert 531a4ab196f6a527304806358f3f0efc5cbeed87

[doutriaux1]

Reverts #1541

when running iPython now I get:

Traceback (most recent call last):
  File "/lgm/uvcdat/2015-11-04/bin/ipython", line 4, in <module>
    from IPython import start_ipython
  File "/lgm/uvcdat/2015-11-04/lib/python2.7/site-packages/IPython/__init__.py", line 47, in <module>
    from .core.application import Application
  File "/lgm/uvcdat/2015-11-04/lib/python2.7/site-packages/IPython/core/application.py", line 22, in <module>
    from traitlets.config.application import Application, catch_config_error
ImportError: No module named traitlets.config.application