function isValidWidthValue(value) {
      return angular.isString(value) || angular.isNumber(value);
    }
@ngdoc method
@methodOf ui.grid.class:GridColumn
@name updateColumnDef
@description Moves settings from the columnDef down onto the column,
and sets properties as appropriate
@param {GridColumn} colDef the column def to look in for the property value
@param {boolean} isNew whether the column is being newly created, if not
we're updating an existing column, and some items such as the sort shouldn't
be copied down