Use '%pylab inline' in GHME 2013 notebook

Without this, the `figsize` will fail if ipython isn't started
'--pylab=inline'.
Remove deprecated argument in GHME 2013 notebook

The `order` keyword wasn't actually used by `factorize`. See
https://github.com/pydata/pandas/issues/6926.
Use get_data_file in GHME 2013 notebook

This input file was renamed in commit ab9f33f. GHME_2013.py was already
updated in ab9f33f.
Merge pull request #606 from kyleam/fix-ghme-nb

Fix issues with 'GHME 2013.ipynb'