function quantile( p, mu, sigma ) {
	return addon( p, mu, sigma );
}
Evaluates the quantile function for a normal distribution with mean `mu` and standard deviation `sigma` at a probability `p`.

@private
@param {Probability} p - input value
@param {number} mu - mean
@param {NonNegativeNumber} sigma - standard deviation
@returns {number} evaluated quantile function

@example
var y = quantile( 0.8, 0.0, 1.0 );
// returns ~0.842

@example
var y = quantile( 0.5, 4.0, 2.0 );
// returns 4.0

@example
var y = quantile( 1.1, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( -0.2, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( NaN, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( 0.0, NaN, 1.0 );
// returns NaN

@example
var y = quantile( 0.0, 0.0, NaN );
// returns NaN

@example
// Negative standard deviation:
var y = quantile( 0.5, 0.0, -1.0 );
// returns NaN