added np.asarray call to durbin_watson function
added test case for durbin_watson with pandas closes #777
new test case is actually called now. derp. closes #777
Merge pull request #779 from anov/master

added np.asarray call to durbin_watson in stattools
RLS: Tool for getting github stats for release from IPython
STY: PEP-8 and update for statsmodels