function stringifyColumns (columns, defaultColumnPaths) {
	if (!columns) {
		return;
	}
	// Turns [{ path: 'someColumn' }, { path: 'someOtherColumn' }]
	// into ['someColumn', 'someOtherColumn']
	let columnString = columns.map((column) => column.path);
	// Turns that array into 'someColumn,someOtherColumn'
	if (Array.isArray(columnString)) columnString = columnString.join(',');
	// If that is the same as the default columns, don't set the query param
	if (columnString === defaultColumnPaths) columnString = undefined;
	return columnString;
}
Stringify the columns array from the state

@param  {Array}  columns            The columns from the active state
@param  {String} defaultColumnPaths The default column paths of the current list

@return {String}                    The column array, stringified