function max( x, y ) {
	return ( x < y ) ? y : x; // doesn't account for +-0
}
Returns the maximum value of `x` and `y`.

@private
@param {number} x - first number
@param {number} y - second number
@returns {number} maximum value

@example
var z = max( 3.14, -1.0 );
// returns 3.14