IPython.frontend is deprecated

Newer versions of IPython give the following warning:
UserWarning: The top-level frontend package has been deprecated. All its
subpackages have been moved to the top IPython level. warn("The
top-level frontend package has been deprecated. "

Fix as according to Google.
Merge branch 'BUG_FIX_FEI_reader' into 0.7.1
Merge remote-tracking branch 'vidars/frontend_deprecated' into 0.7.1
Merge branch '0.7.1'