Merge branch 'err_msg' of github.com:naylor-b/OpenMDAO-Framework into err_msg
cleanup of list_deriv_vars stuff
Merge branch 'dev' of github.com:OpenMDAO/OpenMDAO-Framework into err_msg
minor err msg fix
Merge pull request #1649 from naylor-b/err_msg

a little cleanup of list_deriv_vars handling