function getSortString (sort) {
	return sort.paths.map(i => {
		// If we want to sort inverted, we prefix a "-" before the sort path
		return i.invert ? '-' + i.path : i.path;
	}).filter(truthy).join(',');
}
Get the sorting string for the URI

@param  {Array} sort.paths The paths we want to sort

@return {String}           All the sorting queries we want as a string