BUG: For ARMA(0,0) ensure 1d bse and fix summary.
Merge pull request #1583 from jseabold/fix-buglet

BUG: For ARMA(0,0) ensure 1d bse and fix summary.
Changed covstruct argument to cov_struct
Added a bit to the release announcement for GEE
Improved one line of linear algebra
Remove local test code
Update tests
Changed covstruct to cov_struct
Doc string fix
Added diagnostic plot for covariance structure
Rename the plot function
Refactored nominal and ordinal code, added plot function for ordinal
Initial commit
docstring improvements
more docstring improvements
Added corr_thresholded
Updated docstrings
Removed local path
Renamings and docstring fixed
Added comments to release notes