fixed 'Column.sort_url'.
fixed 'Column.sort_url'.

dimagi/rapidsms,lsgunth/rapidsms,catalpainternational/rapidsms,ken-muturi/rapidsms,caktus/rapidsms,caktus/rapidsms,lsgunth/rapidsms,ehealthafrica-ci/rapidsms,ehealthafrica-ci/rapidsms,dimagi/rapidsms-core-dev,rapidsms/rapidsms-core-dev,lsgunth/rapidsms,ken-muturi/rapidsms,peterayeni/rapidsms,unicefuganda/edtrac,unicefuganda/edtrac,peterayeni/rapidsms,dimagi/rapidsms,peterayeni/rapidsms,lsgunth/rapidsms,ehealthafrica-ci/rapidsms,dimagi/rapidsms-core-dev,eHealthAfrica/rapidsms,catalpainternational/rapidsms,peterayeni/rapidsms,rapidsms/rapidsms-core-dev,eHealthAfrica/rapidsms,catalpainternational/rapidsms,unicefuganda/edtrac,ken-muturi/rapidsms,catalpainternational/rapidsms,caktus/rapidsms,eHealthAfrica/rapidsms