function minmax( x, y ) {
	var out = new Float64Array( 2 );
	addon( x, y, out );
	return out;
}
Returns the minimum and maximum values.

@private
@param {number} x - first number
@param {number} y - second number
@returns {Float64Array} minimum and maximum values

@example
var v = minmax( 3.14, 4.2 );
// returns <Float64Array>[ 3.14, 4.2 ]

@example
var v = minmax( 3.14, NaN );
// returns <Float64Array>[ NaN, NaN ]

@example
var v = minmax( +0.0, -0.0 );
// returns <Float64Array>[ -0.0, 0.0 ]