REF: Results.predict convert to array and adjust shape
Merge pull request #1254 from josef-pkt/fix_predict_1032

REF: Results.predict convert to array and adjust shape
Initial GEE commit
Add inverse_deriv
renamings; GEE is subclass of model
minor cleanup
removed some local debugging code
Renaming of exog, exog_li, etc.
Comment out debugging code
Modified summary
Added tests
attempt to fix csv import
removed data files from genmod/tests/data, now in genmod/tests/results
Comment out debugging code
Added score test and constrained estimation to GEE
Fixed signature of estimate_scale
Fixed error in summary method
Forgot to push some updated files
Standardized pandas/numpy conversions
Minor formatting and comment changes