statsmodels/statsmodels — pull request #2034 by jseabold (2014-10-08 22:56:04+00:00)
Title: ENH: Handle missing for extra data with formulas

This should handle all the missing data issues when going through patsy. I know this is mentioned in #1877. Probably elsewhere, but I have to run.

### TODO
- [ ] Add to release notes
- [ ] Add patys missing hard-coded drop to docs somewhere. Maybe FAQ.