pydata/pandas — pull request #6657 by rosnfeld (2014-03-17 23:10:30+00:00)
Title: REGR: fixing Timestamp/Series subtraction, resolves #6648

Resolves #6648.

Admittedly the conditional in ```__sub__``` is a little gross now.

I didn't add release notes as this is really just patching up a yet-to-be released item, but please let me know if I should.

Also, the test only runs on numpy >= 1.7, is that okay?