Merge branch 'develop'

BUG: Add scipy to dependencies

Changes for PYPI upload/install.

Merge branch 'develop'

Increase version number; finalize change log

DOC: Add check_colinear and edit save_mem

BUG: add warning about yhat/resid behavior

REF: unused import

Merge branch 'check-colinear' into develop

Write tests; debug for tests; tests run

begin tests

REF: move colinear functions around

I think colinear is implemented for ols and iv; need tests

Update changelog

rank check for `reg` (not `ivreg` yet)